drm/msm: add support for parsing YUV 420 deep color

Current upstream parser only handles RGB deep color
modes.

Add support in the SDE EDID parser module to parse
HDMI VSDB block and indicate support for YUV 420
deep color modes in the sink.

Change-Id: If6c007263094e7716a29cae503d3e3471ae04306
Signed-off-by: Abhinav Kumar <abhinavk@codeaurora.org>