perf lock: Add "info" subcommand for dumping misc information

This adds the "info" subcommand to perf lock which can be used
to dump metadata like threads or addresses of lock instances.
"map" was removed because info should do the work for it.

This will be useful not only for debugging but also for ordinary
analyzing.

v2: adding example of usage
% sudo ./perf lock info -t
 | Thread ID: comm
 | 	 0: swapper
 |         1: init
 |        18: migration/5
 |        29: events/2
 |        32: events/5
 |        33: events/6
...

% sudo ./perf lock info -m
| Address of instance: name of class
|  0xffff8800b95adae0: &(&sighand->siglock)->rlock
|  0xffff8800bbb41ae0: &(&sighand->siglock)->rlock
|  0xffff8800bf165ae0: &(&sighand->siglock)->rlock
|  0xffff8800b9576a98: &p->cred_guard_mutex
|  0xffff8800bb890a08: &(&p->alloc_lock)->rlock
|  0xffff8800b9522a08: &(&p->alloc_lock)->rlock
|  0xffff8800bb8aaa08: &(&p->alloc_lock)->rlock
|  0xffff8800bba72a08: &(&p->alloc_lock)->rlock
|  0xffff8800bf18ea08: &(&p->alloc_lock)->rlock
|  0xffff8800b8a0d8a0: &(&ip->i_lock)->mr_lock
|  0xffff88009bf818a0: &(&ip->i_lock)->mr_lock
|  0xffff88004c66b8a0: &(&ip->i_lock)->mr_lock
|  0xffff8800bb6478a0: &(shost->host_lock)->rlock

v3: fixed some problems Frederic pointed out
 * better rbtree tracking in dump_threads()
 * removed printf() and used pr_info() and pr_debug()

Signed-off-by: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
LKML-Reference: <1272863520-16179-1-git-send-email-mitake@dcl.info.waseda.ac.jp>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>