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 <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Michael S. Tsirkin <[e-mail]>
Acked-by: Jason Wang <[e-mail]>

drivers/vhost/test.c

···
 	/* 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;
 }