drm/amdgpu/dce_virtual: bypass DPM for vf

If enable DPM for VF, always get lot of warn_slow_patch_null in
dmesg and vf doesn't support DPM.

Signed-off-by: Xiangliang Yu <Xiangliang.Yu@amd.com>
Signed-off-by: Monk Liu <Monk.Liu@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -204,6 +204,9 @@ static void dce_virtual_crtc_dpms(struct drm_crtc *crtc, int mode)
 	struct amdgpu_crtc *amdgpu_crtc = to_amdgpu_crtc(crtc);
 	unsigned type;
 
+	if (amdgpu_sriov_vf(adev))
+		return;
+
 	switch (mode) {
 	case DRM_MODE_DPMS_ON:
 		amdgpu_crtc->enabled = true;