drm/amdgpu: enable vcn clock gating for navi12

enables vcn medium grained clock gating
Signed-off-by: Xiaojie Yuan <xiaojie.yuan@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/nv.c

@@ -654,7 +654,8 @@ static int nv_common_early_init(void *handle)
 			AMD_CG_SUPPORT_MC_MGCG |
 			AMD_CG_SUPPORT_MC_LS |
 			AMD_CG_SUPPORT_ATHUB_MGCG |
-			AMD_CG_SUPPORT_ATHUB_LS;
+			AMD_CG_SUPPORT_ATHUB_LS |
+			AMD_CG_SUPPORT_VCN_MGCG;
 		adev->pg_flags = AMD_PG_SUPPORT_VCN_DPG;
 		adev->external_rev_id = adev->rev_id + 0xa;
 		break;