mm: point the UNEVICTABLE_LRU config option at the documentation

Point the UNEVICTABLE_LRU config option at the documentation describing
the option.

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/Kconfig b/mm/Kconfig
index b53427a..57971d2 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -213,6 +213,8 @@
 	  will use one page flag and increase the code size a little,
 	  say Y unless you know what you are doing.
 
+	  See Documentation/vm/unevictable-lru.txt for more information.
+
 config HAVE_MLOCK
 	bool
 	default y if MMU=y