drm/amdgpu: Add FGCG for GFX v9.4.3

It's not fine grain, behaves similar to MGCG.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Le Ma <le.ma@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>