net: Use rtnl_lock_killable() in register_netdev()

This patch adds rtnl_lock_killable() to one of hot path
using rtnl_lock().

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -8018,7 +8018,8 @@ int register_netdev(struct net_device *dev)
 {
 	int err;
 
-	rtnl_lock();
+	if (rtnl_lock_killable())
+		return -EINTR;
 	err = register_netdevice(dev);
 	rtnl_unlock();
 	return err;