drm/edid: Parse DSC1.2 cap fields from HFVSDB block

drm/edid: Parse DSC1.2 cap fields from HFVSDB block

This patch parses HFVSDB fields for DSC1.2 capabilities of an
HDMI2.1 sink. These fields are required by a source to understand the
DSC capability of the sink, to set appropriate PPS parameters,
before transmitting compressed data stream.

v2: Addressed following issues as suggested by Uma Shankar:
-Added a new struct for hdmi dsc cap
-Fixed bugs in macros usage.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
[Jani: Fixed checkpatch PARENTHESIS_ALIGNMENT.]
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201218103723.30844-4-ankit.k.nautiyal@intel.com