drm/amd/display: Add a missing DCN3.01 API mapping

[why]
Required for DSC MST

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Nikola Cornij <nikola.cornij@amd.com>
Reviewed-by: Zhan Liu <Zhan.Liu@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>