media: ov7670: use v4l2_async_unregister_subdev()

The sub-device for ov7670 is registered by v4l2_async_register_subdev().
So it should be unregistered by v4l2_async_unregister_subdev() instead of
v4l2_device_unregister_subdev().

Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/i2c/ov7670.c

@@ -1820,7 +1820,7 @@ static int ov7670_remove(struct i2c_client *client)
 	struct v4l2_subdev *sd = i2c_get_clientdata(client);
 	struct ov7670_info *info = to_state(sd);
 
-	v4l2_device_unregister_subdev(sd);
+	v4l2_async_unregister_subdev(sd);
 	v4l2_ctrl_handler_free(&info->hdl);
 	clk_disable_unprepare(info->clk);
 #if defined(CONFIG_MEDIA_CONTROLLER)