drm: virtio: fix virtio_gpu_mode_dumb_create

Lookup format using virtio_gpu_translate_format()
instead of hardcoding it.  Fixes xorg display on
bigendian guests (i.e. ppc64).
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: Laurent Vivier <lvivier@redhat.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170403070845.10793-3-kraxel@redhat.com

drivers/gpu/drm/virtio/virtgpu_gem.c

@@ -88,6 +88,7 @@ int virtio_gpu_mode_dumb_create(struct drm_file *file_priv,
 	int ret;
 	uint32_t pitch;
 	uint32_t resid;
+	uint32_t format;
 
 	pitch = args->width * ((args->bpp + 1) / 8);
 	args->size = pitch * args->height;
@@ -98,9 +99,10 @@ int virtio_gpu_mode_dumb_create(struct drm_file *file_priv,
 	if (ret)
 		goto fail;
 
+	format = virtio_gpu_translate_format(DRM_FORMAT_XRGB8888);
 	virtio_gpu_resource_id_get(vgdev, &resid);
-	virtio_gpu_cmd_create_resource(vgdev, resid,
-				       2, args->width, args->height);
+	virtio_gpu_cmd_create_resource(vgdev, resid, format,
+				       args->width, args->height);
 
 	/* attach the object to the resource */
 	obj = gem_to_virtio_gpu_obj(gobj);