net: convert remaining non-symbolic return values in ndo_start_xmit() functions

This patch converts the remaining occurences of raw return values to their
symbolic counterparts in ndo_start_xmit() functions that were missed by the
previous automatic conversion.

Additionally code that assumed the symbolic value of NETDEV_TX_OK to be zero
is changed to explicitly use NETDEV_TX_OK.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/tulip/dmfe.c b/drivers/net/tulip/dmfe.c
index 8e78f00..5e15fab 100644
--- a/drivers/net/tulip/dmfe.c
+++ b/drivers/net/tulip/dmfe.c
@@ -676,7 +676,7 @@
 	if (skb->len > MAX_PACKET_SIZE) {
 		printk(KERN_ERR DRV_NAME ": big packet = %d\n", (u16)skb->len);
 		dev_kfree_skb(skb);
-		return 0;
+		return NETDEV_TX_OK;
 	}
 
 	spin_lock_irqsave(&db->lock, flags);
@@ -722,7 +722,7 @@
 	/* free this SKB */
 	dev_kfree_skb(skb);
 
-	return 0;
+	return NETDEV_TX_OK;
 }