drm/amd/display: assume VBIOS supports DSC as default

[Why & How]
The clear_dsc_setting at boot logic was based on dcn version
check.
As such new ASIC lost this DSC clear up logic, change the
assumption to BIOS support eDP DSC for new ASIC.

Reviewed-by: Alvin Lee <alvin.lee2@amd.com>
Signed-off-by: Charlene Liu <Charlene.Liu@amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>