drm/i915/display: Configure PCON for DSC1.1 to DSC1.2 encoding

drm/i915/display: Configure PCON for DSC1.1 to DSC1.2 encoding

When a source supporting DSC1.1 is connected to DSC1.2 HDMI2.1 sink
via DP HDMI2.1 PCON, the PCON can be configured to decode the
DSC1.1 compressed stream and encode to DSC1.2. It then sends the
DSC1.2 compressed stream to the HDMI2.1 sink.

This patch configures the PCON for DSC1.1 to DSC1.2 encoding, based
on the PCON's DSC encoder capablities and HDMI2.1 sink's DSC decoder
capabilities.

v2: Addressed review comments from Uma Shankar:
-fixed the error in packing pps parameter values
-added check for pcon in the pcon related function
-appended display in commit message

v3: Only consider non-zero DSC FRL b/w for determining max FRL b/w
supported by sink.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
[Jani: Fixed checkpatch BRACES, LINE_SPACING, PARENTHESIS_ALIGNMENT.]
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201218103723.30844-15-ankit.k.nautiyal@intel.com