vhost-test: drop flush after vhost_dev_cleanup

The flush after vhost_dev_cleanup is not needed because:

1. It doesn't do anything. vhost_dev_cleanup will stop the worker thread
so the flush call will just return since the worker has not device.

2. It's not needed. The comment about jobs re-queueing themselves does
not look correct because handle_vq does not requeue work.
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20220517180850.198915-8-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vhost/test.c

@@ -158,9 +158,6 @@ static int vhost_test_release(struct inode *inode, struct file *f)
 	vhost_test_flush(n);
 	vhost_dev_stop(&n->dev);
 	vhost_dev_cleanup(&n->dev);
-	/* We do an extra flush before freeing memory,
-	 * since jobs can re-queue themselves. */
-	vhost_test_flush(n);
 	kfree(n->dev.vqs);
 	kfree(n);
 	return 0;