This patch implements less hostile mutex_lock() and mutex_lock() wrappers on
top of the pthread API equivalents as suggested by Ingo Molnar:

  glibc/pthreads mutex API semantics are pretty silly IMO.

  I *think* it would be better to try to match the kernel API here, and provide
  trivial wrappers around mutex_lock()/mutex_unlock(). We wont ever bring down
  threads in a hostile way, so we wont actually need the error returns. CPU
  threads should probably only exit once the kvm process exits, after all
  cleanup has been done.

  That way usage would be more obvious and more familar to kernel developers :-)

  [ It would also open up the possibility, in the far future, to bring lockdep to
    user-space ;-) ]

Cc: Asias He <asias.hejun@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Pekka Enberg <penberg@kernel.org>