drm/amd/display: Add HDMI DSC native YCbCr422 support

[WHY && HOW]
For some HDMI OVT timing, YCbCr422 encoding fails at the DSC
bandwidth check. The root cause is our DSC policy for timing
doesn't account for HDMI YCbCr422 native support.

Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Reviewed-by: Chris Park <chris.park@amd.com>
Signed-off-by: Leo Ma <hanghong.ma@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>