net: fix "netpoll: Allow netpoll_setup/cleanup recursion"

Remove rtnl_unlock() which had no corresponding rtnl_lock().
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/netpoll.c

@@ -748,7 +748,6 @@ int __netpoll_setup(struct netpoll *np)
 
 	/* last thing to do is link it to the net device structure */
 	rcu_assign_pointer(ndev->npinfo, npinfo);
-	rtnl_unlock();
 
 	return 0;