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/sundance.c b/drivers/net/sundance.c
index 545f81b..0df6332 100644
--- a/drivers/net/sundance.c
+++ b/drivers/net/sundance.c
@@ -1091,7 +1091,7 @@
 			"%s: Transmit frame #%d queued in slot %d.\n",
 			dev->name, np->cur_tx, entry);
 	}
-	return 0;
+	return NETDEV_TX_OK;
 }
 
 /* Reset hardware tx and free all of tx buffers */