drm/amd/display: Add DSC_DBG_EN shift/mask for dcn3

This field is not defined for DCN3

Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2 files changed