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/irda/irda-usb.c b/drivers/net/irda/irda-usb.c
index 0c0831c..6a1aa7a 100644
--- a/drivers/net/irda/irda-usb.c
+++ b/drivers/net/irda/irda-usb.c
@@ -534,7 +534,7 @@
 	}
 	spin_unlock_irqrestore(&self->lock, flags);
 	
-	return 0;
+	return NETDEV_TX_OK;
 
 drop:
 	/* Drop silently the skb and exit */