FROMLIST: drm: Parse HDMI 2.0 YCbCr 4:2:0 VDB and VCB

FROMLIST: drm: Parse HDMI 2.0 YCbCr 4:2:0 VDB and VCB

HDMI 2.0 introduces a new sampling mode called YCbCr 4:2:0.
According to the spec the EDID may contain two blocks that
signal this sampling mode:
	- YCbCr 4:2:0 Video Data Block
	- YCbCr 4:2:0 Video Capability Map Data Block

The video data block contains the list of vic's were
only YCbCr 4:2:0 sampling mode shall be used while the
video capability map data block contains a mask were
YCbCr 4:2:0 sampling mode may be used.

This RFC patch adds support for parsing these two new blocks
and introduces new flags to signal the drivers if the
mode is 4:2:0'only or 4:2:0'able.

The reason this is still a RFC is because there is no
reference in kernel for this new sampling mode (specially in
AVI infoframe part), so, I was hoping to hear some feedback
first.

Tested in a HDMI 2.0 compliance scenario.

Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Cc: Carlos Palminha <palminha@synopsys.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org
(am from https://patchwork.kernel.org/patch/9495175)
Change-Id: I7c9e331b5bf5f1fbcefd4368bc4b82ff180eb91e
Signed-off-by: Zheng Yang <zhengyang@rock-chips.com>