drm/amd/display: Add dsc_to_stream_resource for dcn3

Without this, enabling dsc will cause a nullptr

Reviewed-by: Mikita Lipski <Mikita.Lipski@amd.com>
Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>