add "Isolate" migratetype name to /proc/pagetypeinfo

In a5d76b54a3f3a40385d7f76069a2feac9f1bad63 (memory unplug: page isolation by
KAMEZAWA Hiroyuki), "isolate" migratetype added.  but unfortunately, it
doesn't treat /proc/pagetypeinfo display logic.

this patch add "Isolate" to pagetype name field.

/proc/pagetype
before:
------------------------------------------------------------------------------------------------------------------------
Free pages count per migrate type at order       0      1      2      3      4      5      6      7      8      9     10
Node    0, zone      DMA, type    Unmovable      1      2      2      2      1      2      2      1      1      0      0
Node    0, zone      DMA, type  Reclaimable      0      0      0      0      0      0      0      0      0      0      0
Node    0, zone      DMA, type      Movable      2      3      3      1      3      3      2      0      0      0      0
Node    0, zone      DMA, type      Reserve      0      0      0      0      0      0      0      0      0      0      1
Node    0, zone      DMA, type       <NULL>      0      0      0      0      0      0      0      0      0      0      0
Node    0, zone   Normal, type    Unmovable      1      9      7      4      1      1      1      1      0      0      0
Node    0, zone   Normal, type  Reclaimable      5      2      0      0      1      1      0      0      0      1      0
Node    0, zone   Normal, type      Movable      0      1      1      0      0      0      1      0      0      1     60
Node    0, zone   Normal, type      Reserve      0      0      0      0      0      0      0      0      0      0      1
Node    0, zone   Normal, type       <NULL>      0      0      0      0      0      0      0      0      0      0      0
Node    0, zone  HighMem, type    Unmovable      0      0      1      1      1      0      1      1      2      2      0
Node    0, zone  HighMem, type  Reclaimable      0      0      0      0      0      0      0      0      0      0      0
Node    0, zone  HighMem, type      Movable    236     62      6      2      2      1      1      0      1      1     16
Node    0, zone  HighMem, type      Reserve      0      0      0      0      0      0      0      0      0      0      1
Node    0, zone  HighMem, type       <NULL>      0      0      0      0      0      0      0      0      0      0      0

Number of blocks type     Unmovable  Reclaimable      Movable      Reserve       <NULL>
Node 0, zone      DMA            1            0            2       1            0
Node 0, zone   Normal           10           40          169       1            0
Node 0, zone  HighMem            2            0          283       1            0

after:
------------------------------------------------------------------------------------------------------------------------
Free pages count per migrate type at order       0      1      2      3      4      5      6      7      8      9     10
Node    0, zone      DMA, type    Unmovable      1      2      2      2      1      2      2      1      1      0      0
Node    0, zone      DMA, type  Reclaimable      0      0      0      0      0      0      0      0      0      0      0
Node    0, zone      DMA, type      Movable      2      3      3      1      3      3      2      0      0      0      0
Node    0, zone      DMA, type      Reserve      0      0      0      0      0      0      0      0      0      0      1
Node    0, zone      DMA, type      Isolate      0      0      0      0      0      0      0      0      0      0      0
Node    0, zone   Normal, type    Unmovable      0      2      1      1      0      1      0      0      0      0      0
Node    0, zone   Normal, type  Reclaimable      1      1      1      1      1      0      1      1      1      0      0
Node    0, zone   Normal, type      Movable      0      1      1      1      0      1      0      1      0      0    196
Node    0, zone   Normal, type      Reserve      0      0      0      0      0      0      0      0      0      0      1
Node    0, zone   Normal, type      Isolate      0      0      0      0      0      0      0      0      0      0      0
Node    0, zone  HighMem, type    Unmovable      0      1      0      0      0      1      1      1      2      2      0
Node    0, zone  HighMem, type  Reclaimable      0      0      0      0      0      0      0      0      0      0      0
Node    0, zone  HighMem, type      Movable      1      0      1      1      0      0      0      0      1      0    200
Node    0, zone  HighMem, type      Reserve      0      0      0      0      0      0      0      0      0      0      1
Node    0, zone  HighMem, type      Isolate      0      0      0      0      0      0      0      0      0      0      0

Number of blocks type     Unmovable  Reclaimable      Movable      Reserve      Isolate
Node 0, zone      DMA            1            0            2       1            0
Node 0, zone   Normal            8            4          207       1            0
Node 0, zone  HighMem            2            0          283       1            0

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 422d960..7c7286e 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -388,6 +388,7 @@
 	"Reclaimable",
 	"Movable",
 	"Reserve",
+	"Isolate",
 };
 
 static void *frag_start(struct seq_file *m, loff_t *pos)