perf lock: Document lock info subcommand

perf lock: Document lock info subcommand

The commit 27b9c2ca72ce7 ("perf lock: Add "info" subcommand for dumping
misc information") added the subcommand but missed documentation. Add
it. Also update stale 'trace' subcommand to 'script'.

Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1327827356-8786-5-git-send-email-namhyung@gmail.com
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>