net: use NETDEV_TX_OK instead of 0 in ndo_start_xmit() functions

This patch is the result of an automatic spatch transformation to convert
all ndo_start_xmit() return values of 0 to NETDEV_TX_OK.

Some occurences are missed by the automatic conversion, those will be
handled in a seperate patch.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/phonet/pep-gprs.c b/net/phonet/pep-gprs.c
index 480839d..4667af5 100644
--- a/net/phonet/pep-gprs.c
+++ b/net/phonet/pep-gprs.c
@@ -195,7 +195,7 @@
 		break;
 	default:
 		dev_kfree_skb(skb);
-		return 0;
+		return NETDEV_TX_OK;
 	}
 
 	skb_orphan(skb);
@@ -215,7 +215,7 @@
 	netif_stop_queue(dev);
 	if (pep_writeable(sk))
 		netif_wake_queue(dev);
-	return 0;
+	return NETDEV_TX_OK;
 }
 
 static int gprs_set_mtu(struct net_device *dev, int new_mtu)