msm: camera: isp: Changes to adapt to new AVTimer Driver API

A new AVTimer driver API has been provided which directly provides
the timestamp value in ticks that can be converted to appropriate
timescale and tagged to the video frames.

Change-Id: I9923c066602819eed0ccd06e112f12cd85b3d71b
CRs-fixed: 686642
Signed-off-by: Venu Yeshala <vyeshala@codeaurora.org>