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 <[e-mail]>
Signed-off-by: ran jianping <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/rmi4/rmi_f54.c

···
 	v4l2_device_unregister(&f54->v4l2);
 remove_wq:
 	cancel_delayed_work_sync(&f54->work);
-	flush_workqueue(f54->workqueue);
 	destroy_workqueue(f54->workqueue);
 	return ret;
 }