drm/amdgpu: fix a amdgpu_dpm=0 bug

Signed-off-by: Sonny Jiang <sonny.jiang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -557,9 +557,11 @@ static int cz_dpm_late_init(void *handle)
 {
 	struct amdgpu_device *adev = (struct amdgpu_device *)handle;
 
+	if (amdgpu_dpm) {
 		/* powerdown unused blocks for now */
 		cz_dpm_powergate_uvd(adev, true);
 		cz_dpm_powergate_vce(adev, true);
+	}
 
 	return 0;
 }