Documentation: fix the VM knobs descritpion WRT pdflush

The pdflush thread is long gone, however we still mention it incorrectly in the
kernel documentation. This patch fixes the situation.

Cc: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/Documentation/laptops/laptop-mode.txt b/Documentation/laptops/laptop-mode.txt
index 0bf25ee..4ebbfc3 100644
--- a/Documentation/laptops/laptop-mode.txt
+++ b/Documentation/laptops/laptop-mode.txt
@@ -262,9 +262,9 @@
 
 #
 # Allowed dirty background ratio, in percent.  Once DIRTY_RATIO has been
-# exceeded, the kernel will wake pdflush which will then reduce the amount
-# of dirty memory to dirty_background_ratio.  Set this nice and low, so once
-# some writeout has commenced, we do a lot of it.
+# exceeded, the kernel will wake flusher threads which will then reduce the
+# amount of dirty memory to dirty_background_ratio.  Set this nice and low,
+# so once some writeout has commenced, we do a lot of it.
 #
 #DIRTY_BACKGROUND_RATIO=5
 
@@ -384,9 +384,9 @@
 
 #
 # Allowed dirty background ratio, in percent.  Once DIRTY_RATIO has been
-# exceeded, the kernel will wake pdflush which will then reduce the amount
-# of dirty memory to dirty_background_ratio.  Set this nice and low, so once
-# some writeout has commenced, we do a lot of it.
+# exceeded, the kernel will wake flusher threads which will then reduce the
+# amount of dirty memory to dirty_background_ratio.  Set this nice and low,
+# so once some writeout has commenced, we do a lot of it.
 #
 DIRTY_BACKGROUND_RATIO=${DIRTY_BACKGROUND_RATIO:-'5'}