drm/amd/display: Enable DSC over eDP

drm/amd/display: Enable DSC over eDP

[why]
- Adding a DM interface to enable DSC over eDP on Linux
- DSC over eDP will allow to power savings by reducing
the bandwidth required to support panel's modes
- Apply link optimization algorithm to reduce link bandwidth
when DSC is enabled

[how]
- Read eDP panel's DSC capabilities
- Apply DSC policy on eDP panel based on its DSC capabilities
- Enable DSC encoder's on the pipe
- Enable DSC on panel's side by setting DSC_ENABLE DPCD register
- Adding link optimization algorithm to reduce link rate or lane
count based

Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Mikita Lipski <mikita.lipski@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>