drm/msm: add YUV format support for HDMI

This change adds YUV format support for HDMI.
Also, chooses the best mode for turning on the
sink based on sink source capabilities. This
can be either RGB or YUV. For YUV formats adjust
the pixel clock and also configure the relevant
hardware blocks in SDE.

Change-Id: I48a36a991c194badb3ddca4bbf5bcbc21d838b8f
Signed-off-by: Yuan Zhao <yzhao@codeaurora.org>