lockstat: documentation

Provide some documentation for CONFIG_LOCK_STAT.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Cc: Rob Landley <rob@landley.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 495863a..cdc9b09 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -294,6 +294,8 @@
 	help
 	 This feature enables tracking lock contention points
 
+	 For more details, see Documentation/lockstat.txt
+
 config DEBUG_LOCKDEP
 	bool "Lock dependency engine debugging"
 	depends on DEBUG_KERNEL && LOCKDEP