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/hamradio/baycom_epp.c b/drivers/net/hamradio/baycom_epp.c
index 5e4b7af..e229edf 100644
--- a/drivers/net/hamradio/baycom_epp.c
+++ b/drivers/net/hamradio/baycom_epp.c
@@ -774,18 +774,18 @@
 	if (skb->data[0] != 0) {
 		do_kiss_params(bc, skb->data, skb->len);
 		dev_kfree_skb(skb);
-		return 0;
+		return NETDEV_TX_OK;
 	}
 	if (bc->skb)
 		return NETDEV_TX_LOCKED;
 	/* strip KISS byte */
 	if (skb->len >= HDLCDRV_MAXFLEN+1 || skb->len < 3) {
 		dev_kfree_skb(skb);
-		return 0;
+		return NETDEV_TX_OK;
 	}
 	netif_stop_queue(dev);
 	bc->skb = skb;
-	return 0;
+	return NETDEV_TX_OK;
 }
 
 /* --------------------------------------------------------------------- */