msm: camera: Add support for YV12 image format.

If the application uses YV12 or similar image
formats which have more than 2 planes, then enable
all the 3 channels of VFE output.

Change-Id: I31af22a4047a38a12fe09a0b07a68f435506aad1
Signed-off-by: Kiran Kumar H N <hurlisal@codeaurora.org>