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/s390/net/ctcm_main.c b/drivers/s390/net/ctcm_main.c
index 222e473..38b5079 100644
--- a/drivers/s390/net/ctcm_main.c
+++ b/drivers/s390/net/ctcm_main.c
@@ -880,7 +880,7 @@
 				"%s(%s): NULL sk_buff passed",
 					CTCM_FUNTAIL, dev->name);
 		priv->stats.tx_dropped++;
-		return 0;
+		return NETDEV_TX_OK;
 	}
 	if (skb_headroom(skb) < (LL_HEADER_LENGTH + 2)) {
 		CTCM_DBF_TEXT_(ERROR, CTC_DBF_ERROR,
@@ -888,7 +888,7 @@
 			CTCM_FUNTAIL, dev->name, LL_HEADER_LENGTH + 2);
 		dev_kfree_skb(skb);
 		priv->stats.tx_dropped++;
-		return 0;
+		return NETDEV_TX_OK;
 	}
 
 	/*
@@ -901,7 +901,7 @@
 		priv->stats.tx_dropped++;
 		priv->stats.tx_errors++;
 		priv->stats.tx_carrier_errors++;
-		return 0;
+		return NETDEV_TX_OK;
 	}
 
 	if (ctcm_test_and_set_busy(dev))
@@ -910,7 +910,7 @@
 	dev->trans_start = jiffies;
 	if (ctcm_transmit_skb(priv->channel[WRITE], skb) != 0)
 		return NETDEV_TX_BUSY;
-	return 0;
+	return NETDEV_TX_OK;
 }
 
 /* unmerged MPC variant of ctcm_tx */
@@ -1008,7 +1008,7 @@
 	if (do_debug)
 		MPC_DBF_DEV_NAME(TRACE, dev, "exit");
 
-	return 0;	/* handle freeing of skb here */
+	return NETDEV_TX_OK;	/* handle freeing of skb here */
 }