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/wireless/wl3501_cs.c b/drivers/net/wireless/wl3501_cs.c
index e3e96bb..a83a562 100644
--- a/drivers/net/wireless/wl3501_cs.c
+++ b/drivers/net/wireless/wl3501_cs.c
@@ -1348,7 +1348,6 @@
 	if (rc) {
 		++dev->stats.tx_dropped;
 		netif_stop_queue(dev);
-		rc = NETDEV_TX_OK;
 	} else {
 		++dev->stats.tx_packets;
 		dev->stats.tx_bytes += skb->len;
@@ -1358,7 +1357,7 @@
 			netif_stop_queue(dev);
 	}
 	spin_unlock_irqrestore(&this->lock, flags);
-	return rc;
+	return NETDEV_TX_OK;
 }
 
 static int wl3501_open(struct net_device *dev)