msm: camera: fd: Add mutex protection to frame done processing

Frame done processing command need to be synchronized with
fd deinit command. This changes avoids the deinit to fd hardware
during the frame done call back process.

Change-Id: I291077fa1bd2c08d9ee74a1689b4b2008dd7321f
Signed-off-by: Ravikishore Pampana <rpampana@codeaurora.org>