msm: camera2: cpp: support delayed append of buffer in COMPAT

The COMPAT mode needs to be supported for existing IOCTL,
VIDIOC_MSM_CPP_APPEND_STREAM_BUFF_INFO. This will avoid errors
in COMPAT mode when the corresponding IOCTL is invoked.

Change-Id: I1b8d5a7ef4532bdf9265874dee50905ad4ac9908
Signed-off-by: Rajakumar Govindaram <rajakuma@codeaurora.org>