vhost/test: fix memory leak of vhost virtqueues

We need free the vqs in .release(), which are allocated in .open().

Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
Link: https://lore.kernel.org/r/20211228030924.3468439-1-xianting.tian@linux.alibaba.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>

drivers/vhost/test.c

@@ -166,6 +166,7 @@ static int vhost_test_release(struct inode *inode, struct file *f)
 	/* 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;
 }