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/pci-skeleton.c b/drivers/net/pci-skeleton.c
index 8c1f698..e4a93b8 100644
--- a/drivers/net/pci-skeleton.c
+++ b/drivers/net/pci-skeleton.c
@@ -1356,7 +1356,7 @@
 	DPRINTK ("%s: Queued Tx packet at %p size %u to slot %d.\n",
 		 dev->name, skb->data, skb->len, entry);
 
-	return 0;
+	return NETDEV_TX_OK;
 }