Register callback in gfxhub functions to program the bypass groups in
gc_utcl2 corresponding to harvested SA.

v2: update comments (Alex)
Signed-off-by: Xiaomeng Hou <Xiaomeng.Hou@amd.com>
Signed-off-by: Aaron Liu <aaron.liu@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>