perf lock: Fix and add misc documentally things

I've forgot to add 'perf lock' line to command-list.txt,
so users of perf could not find perf lock when they type 'perf'.

Fixing command-list.txt requires document
(tools/perf/Documentation/perf-lock.txt).
But perf lock is too much "under construction" to write a
stable document, so this is something like pseudo document for now.

And I wrote description of perf lock at help section of
CONFIG_LOCK_STAT, this will navigate users of lock trace events.

Signed-off-by: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
LKML-Reference: <1265267295-8388-1-git-send-email-mitake@dcl.info.waseda.ac.jp>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 25c3ed5..65f964e 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -520,6 +520,12 @@
 
 	 For more details, see Documentation/lockstat.txt
 
+	 You can analyze lock events with "perf lock", subcommand of perf.
+	 If you want to use "perf lock", you need to turn on CONFIG_EVENT_TRACING.
+
+	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
+ 	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
+
 config DEBUG_LOCKDEP
 	bool "Lock dependency engine debugging"
 	depends on DEBUG_KERNEL && LOCKDEP