drm/amdgpu/gfx10: add clockgating support for sienna_cichlid

Same as navi10.
Signed-off-by: Likun Gao <Likun.Gao@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c

@@ -7154,6 +7154,7 @@ static int gfx_v10_0_set_clockgating_state(void *handle,
 	case CHIP_NAVI10:
 	case CHIP_NAVI14:
 	case CHIP_NAVI12:
+	case CHIP_SIENNA_CICHLID:
 		gfx_v10_0_update_gfx_clock_gating(adev,
 						 state == AMD_CG_STATE_GATE);
 		break;