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: NDavid 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: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/Kconfig

@@ -213,6 +213,8 @@ config UNEVICTABLE_LRU
 	  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