net: propagate dev_get_valid_name return code

if dev_get_valid_name failed, propagate its return code

and remove the setting err to ENODEV, it will be set to
0 again before dev_change_net_namespace exits.
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -8643,7 +8643,8 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
 		/* We get here if we can't use the current device name */
 		if (!pat)
 			goto out;
-		if (dev_get_valid_name(net, dev, pat) < 0)
+		err = dev_get_valid_name(net, dev, pat);
+		if (err < 0)
 			goto out;
 	}
 
@@ -8655,7 +8656,6 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
 	dev_close(dev);
 
 	/* And unlink it from device chain */
-	err = -ENODEV;
 	unlist_netdevice(dev);
 
 	synchronize_net();