msm_camera: Skip the frame when ping-pong register status is not proper.

When YV12 preview format is set,due to timing reasons the viewfinder frame
status is inconsistent.so skip such frames to avoid preview freeze.

Change-Id: Iac65277b76b1c32eefe95b0932149b7152e4b2e7
Signed-off-by: Monika Alekhya <malekh@codeaurora.org>