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/dummy.c b/drivers/net/dummy.c
index 8ebd7d7..713ce6c 100644
--- a/drivers/net/dummy.c
+++ b/drivers/net/dummy.c
@@ -85,7 +85,7 @@
 	dev->stats.tx_bytes += skb->len;
 
 	dev_kfree_skb(skb);
-	return 0;
+	return NETDEV_TX_OK;
 }
 
 static int dummy_validate(struct nlattr *tb[], struct nlattr *data[])