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/net/netrom/nr_dev.c b/net/netrom/nr_dev.c
index 3513724..c7b7838 100644
--- a/net/netrom/nr_dev.c
+++ b/net/netrom/nr_dev.c
@@ -177,13 +177,13 @@
 	if (!nr_route_frame(skb, NULL)) {
 		kfree_skb(skb);
 		stats->tx_errors++;
-		return 0;
+		return NETDEV_TX_OK;
 	}
 
 	stats->tx_packets++;
 	stats->tx_bytes += len;
 
-	return 0;
+	return NETDEV_TX_OK;
 }
 
 static const struct header_ops nr_header_ops = {