msm:camera: Add support for AV time stamp for VT call

For vt call we need to update the camera buffers with AVTimer
timestamp instead of normal kernel time stamp to prevent
AV sync issues

Change-Id: I4aecf03c45b7dc36c255b122385cee561c7ae40f
Signed-off-by: Abhishek Kondaveeti <akondave@codeaurora.org>
Signed-off-by: Lokesh Kumar Aakulu <lkumar@codeaurora.org>