tun: Fix xdp_rxq_info's queue_index when detaching

When a queue(tfile) is detached, we only update tfile's queue_index,
but do not update xdp_rxq_info's queue_index. This patch fixes it.

Fixes: 8bf5c4ee ("tun: setup xdp_rxq_info")
Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
Link: https://lore.kernel.org/r/1708398727-46308-1-git-send-email-wangyunjian@huawei.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/tun.c

@@ -653,6 +653,7 @@ static void __tun_detach(struct tun_file *tfile, bool clean)
 				   tun->tfiles[tun->numqueues - 1]);
 		ntfile = rtnl_dereference(tun->tfiles[index]);
 		ntfile->queue_index = index;
+		ntfile->xdp_rxq.queue_index = index;
 		rcu_assign_pointer(tun->tfiles[tun->numqueues - 1],
 				   NULL);