msm: camera: Handle wake_up with spin locks

Command ack queue is deleted before wake_up is
completed and leads to kernel crash with bad magic
in spin lock. Fix this by using spinlock with the
command ack queue lock.

Change-Id: I119d38d69fc7a133977b41d62466fbc863f57de4
Signed-off-by: Hariram Purushothaman <hpurus@codeaurora.org>