msm: camera: Use mutex lock to avoid race condition

Use mutex lock before using queuing ioctls like
queuing, dequeing buffers to avoid race condition.

CRs-Fixed: 2038086
Change-Id: Ia9fdfd5a766add2f8d99003b0c2bfe7d34d57a09
Signed-off-by: Krupal Divvela <kdivvela@codeaurora.org>
Signed-off-by: VijayaKumar T M <vtmuni@codeaurora.org>