drm/amd/amdgpu: Fix the CGCG setting is overwritten for SRIOV.

For SRIOV, since the CP_INT_CNTL_RING0 is programed on host side.
The Guest should not program CP_INT_CNTL_RING0 again.

Signed-off-by: Gavin Wan <Gavin.Wan@amd.com>
Reviewed-by: Monk Liu <Monk.Liu@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>