drm/msm: add YUV422 format support

Add DRM_MODE_FLAG_SUPPORTS_YUV422 flag to all EDID modes
if downstream device support YUV422 format.
Add support to configure CDM block to output YUV422 format.

Also capture max bits per channel supported for YUV420 modes.

Change-Id: I76bffbf9bf04267978bb364412d24b40ab845963
Signed-off-by: Narender Ankam <nankam@codeaurora.org>
Signed-off-by: Chirag Khurana <ckhurana@codeaurora.org>