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/drivers/net/wireless/zd1201.c b/drivers/net/wireless/zd1201.c
index 4430b8d9..dae1bfb 100644
--- a/drivers/net/wireless/zd1201.c
+++ b/drivers/net/wireless/zd1201.c
@@ -789,7 +789,7 @@
 	if (!zd->mac_enabled || zd->monitor) {
 		dev->stats.tx_dropped++;
 		kfree_skb(skb);
-		return 0;
+		return NETDEV_TX_OK;
 	}
 	netif_stop_queue(dev);
 
@@ -826,7 +826,7 @@
 	}
 	kfree_skb(skb);
 
-	return 0;
+	return NETDEV_TX_OK;
 }
 
 static void zd1201_tx_timeout(struct net_device *dev)