um: vector: always reset vp->opened

If open fails, we have already set vp->opened, but it's
not reset so that any further attempts will just return
-ENXIO. Reset vp->opened even if close has nothing to do.

This helps e.g. with slirp4netns handling only a single
connection, you can then restart it and open the device
again.

Link: https://patch.msgid.link/20240703184622.df40c5c38461.Id4e20b48938c6019d99e6133227a34ac059db466@changeidAcked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

arch/um/drivers/vector_kern.c

@@ -1119,6 +1119,8 @@ static int vector_net_close(struct net_device *dev)
 	netif_stop_queue(dev);
 	del_timer(&vp->tl);
 
+	vp->opened = false;
+
 	if (vp->fds == NULL)
 		return 0;
 
@@ -1157,7 +1159,6 @@ static int vector_net_close(struct net_device *dev)
 		destroy_queue(vp->tx_queue);
 	kfree(vp->fds);
 	vp->fds = NULL;
-	vp->opened = false;
 	vp->in_error = false;
 	return 0;
 }