drm/amd/display: populate VABC support in DMCUB

[HOW&WHY]
Stores DMUB support for enablement of Varibright over VABC in DCN32

Reviewed-by: Aric Cyr <aric.cyr@amd.com>
Reviewed-by: Iswara Nagulendran <iswara.nagulendran@amd.com>
Signed-off-by: Harry VanZyllDeJong <hvanzyll@amd.com>
Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>