net: fix network drivers ndo_start_xmit() return values (part 7)

Fix up ATM drivers that return an errno value to qdisc_restart(), causing
qdisc_restart() to print a warning an requeue/retransmit the skb.

- lec: condition can only be remedied by userspace, until that retransmissions

Compile tested only.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/atm/lec.c

@@ -270,7 +270,8 @@ static int lec_start_xmit(struct sk_buff *skb, struct net_device *dev)
 		printk("%s:No lecd attached\n", dev->name);
 		dev->stats.tx_errors++;
 		netif_stop_queue(dev);
-		return -EUNATCH;
+		kfree_skb(skb);
+		return NETDEV_TX_OK;
 	}
 
 	pr_debug("skbuff head:%lx data:%lx tail:%lx end:%lx\n",