net: fix network drivers ndo_start_xmit() return values

Fix up remaining drivers returning a magic or an errno value from their
ndo_start_xmit() functions that were missed in the first pass:

- isdn_net: missed conversion
- bpqether: missed conversion: skb is freed, so return NETDEV_TX_OK
- hp100: intention appears to be to resubmit skb once resources are
  available, but due to no queue handling it is dropped for now.
- lapbether: skb is freed, so return NETDEV_TX_OK

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

drivers/net/wan/lapbether.c

@@ -149,46 +149,40 @@ static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb)
  */
 static int lapbeth_xmit(struct sk_buff *skb, struct net_device *dev)
 {
-	int err = -ENODEV;
+	int err;
 
 	/*
 	 * Just to be *really* sure not to send anything if the interface
 	 * is down, the ethernet device may have gone.
 	 */
-	if (!netif_running(dev)) {
+	if (!netif_running(dev))
 		goto drop;
-	}
 
 	switch (skb->data[0]) {
 	case 0x00:
-		err = 0;
 		break;
 	case 0x01:
 		if ((err = lapb_connect_request(dev)) != LAPB_OK)
 			printk(KERN_ERR "lapbeth: lapb_connect_request "
 			       "error: %d\n", err);
-		goto drop_ok;
+		goto drop;
 	case 0x02:
 		if ((err = lapb_disconnect_request(dev)) != LAPB_OK)
 			printk(KERN_ERR "lapbeth: lapb_disconnect_request "
 			       "err: %d\n", err);
 		/* Fall thru */
 	default:
-		goto drop_ok;
+		goto drop;
 	}
 
 	skb_pull(skb, 1);
 
 	if ((err = lapb_data_request(dev, skb)) != LAPB_OK) {
 		printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err);
-		err = -ENOMEM;
 		goto drop;
 	}
-	err = 0;
 out:
-	return err;
-drop_ok:
-	err = 0;
+	return NETDEV_TX_OK;
 drop:
 	kfree_skb(skb);
 	goto out;