liblockdep: Add public headers for pthread_mutex_t implementation

These headers provide the same API as their pthread mutex
counterparts.

The design here is to allow to easily switch to liblockdep lock
validation just by adding a "liblockdep_" to pthread_mutex_*()
calls, which means that it's easy to integrate liblockdep into
existing codebases.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/1371163284-6346-4-git-send-email-sasha.levin@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>