msm: camera2: cpp: Add IOCTL to pop stream buffer in cpp driver.

This IOCTL provides interface for userspace cpp driver to pop
a buffer from stream buffer queue and do buf done.

Change-Id: If2f8deb59a2f64aa40dc2ed2beec19f37c67c5ce
Signed-off-by: Rajakumar Govindaram <rajakuma@codeaurora.org>
Signed-off-by: Mansoor Aftab <maftab@codeaurora.org>