NET: netpoll, fix potential NULL ptr dereference

Stanse found that one error path in netpoll_setup dereferences npinfo
even though it is NULL. Avoid that by adding new label and go to that
instead.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Daniel Borkmann <danborkmann@googlemail.com>
Cc: David S. Miller <davem@davemloft.net>
Acked-by: chavey@google.com
Acked-by: NMatt Mackall <mpm@selenic.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/netpoll.c

@@ -735,7 +735,7 @@ int netpoll_setup(struct netpoll *np)
 		npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 		if (!npinfo) {
 			err = -ENOMEM;
-			goto release;
+			goto put;
 		}
 
 		npinfo->rx_flags = 0;
@@ -845,7 +845,7 @@ int netpoll_setup(struct netpoll *np)
 
 		kfree(npinfo);
 	}
-
+put:
 	dev_put(ndev);
 	return err;
 }