drm/amdgpu: Do not write to GRBM_CNTL if Aldebaran SRIOV

Aldebaran SRIOV VF does not have write permissions to GRBM_CTNL.
This access can be skipped to avoid a dmesg warning.

v2: Use GC IP version check instead of asic check

Signed-off-by: Victor Lu <victorchengchi.lu@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>