Input: synaptics-rmi4 - remove unnecessary flush_workqueue()

All work currently pending will be done first by calling destroy_workqueue,
so there is unnecessary to flush it explicitly.
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: ran jianping <ran.jianping@zte.com.cn>
Link: https://lore.kernel.org/r/20220422093304.2781183-1-ran.jianping@zte.com.cnSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/rmi4/rmi_f54.c

@@ -733,7 +733,6 @@ static int rmi_f54_probe(struct rmi_function *fn)
 	v4l2_device_unregister(&f54->v4l2);
 remove_wq:
 	cancel_delayed_work_sync(&f54->work);
-	flush_workqueue(f54->workqueue);
 	destroy_workqueue(f54->workqueue);
 	return ret;
 }