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/8139too.c b/drivers/net/8139too.c
index 8ae72ec..1a223cd 100644
--- a/drivers/net/8139too.c
+++ b/drivers/net/8139too.c
@@ -1706,7 +1706,7 @@
 	} else {
 		dev_kfree_skb(skb);
 		dev->stats.tx_dropped++;
-		return 0;
+		return NETDEV_TX_OK;
 	}
 
 	spin_lock_irqsave(&tp->lock, flags);
@@ -1731,7 +1731,7 @@
 		pr_debug("%s: Queued Tx packet size %u to slot %d.\n",
 			dev->name, len, entry);
 
-	return 0;
+	return NETDEV_TX_OK;
 }