drm/amd/powerplay: gfxoff-seperate the Vega20 case

seperate the Vega20 case from navi10 for gfxoff so that gfxoff
won't be allowed on Vega20
Signed-off-by: Kenneth Feng <kenneth.feng@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/powerplay/smu_v11_0.c

@@ -1550,13 +1550,24 @@ smu_v11_0_set_watermarks_for_clock_ranges(struct smu_context *smu, struct
 static int smu_v11_0_gfx_off_control(struct smu_context *smu, bool enable)
 {
 	int ret = 0;
+	struct amdgpu_device *adev = smu->adev;
 
+	switch (adev->asic_type) {
+	case CHIP_VEGA20:
+		break;
+	case CHIP_NAVI10:
+		if (!(adev->pm.pp_feature & PP_GFXOFF_MASK))
+			return 0;
 		mutex_lock(&smu->mutex);
 		if (enable)
 			ret = smu_send_smc_msg(smu, SMU_MSG_AllowGfxOff);
 		else
 			ret = smu_send_smc_msg(smu, SMU_MSG_DisallowGfxOff);
 		mutex_unlock(&smu->mutex);
+		break;
+	default:
+		break;
+	}
 
 	return ret;
 }