drm/amdgpu/gfx10: set gfx cg for navi12

Same as other navi asics.
Signed-off-by: NXiaojie Yuan <xiaojie.yuan@amd.com>
Reviewed-by: NHawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

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

@@ -4149,6 +4149,7 @@ static int gfx_v10_0_set_clockgating_state(void *handle,
 	switch (adev->asic_type) {
 	case CHIP_NAVI10:
 	case CHIP_NAVI14:
+	case CHIP_NAVI12:
 		gfx_v10_0_update_gfx_clock_gating(adev,
 						 state == AMD_CG_STATE_GATE ? true : false);
 		break;