drm/amd/display: Add AS SDP programming for UHBR link rate.

Add SDP programming for UHB link as well.

Reviewed-by: Wenjing Liu <wenjing.liu@amd.com>
Signed-off-by: Ian Chen <ian.chen@amd.com>
Signed-off-by: Wayne Lin <wayne.lin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>