msm: camera: Avoid deadlock for vb2 operations using separate lock

Use mutex lock for all VB2 operations, and use separatelock other
than used for stop streaming operation to avoid dead lock.

Change-Id: Idba956e5e3bce48ee57eaa5984786ded218e32d5
Signed-off-by: annamraj <annamraj@codeaurora.org>