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/irda/nsc-ircc.c b/drivers/net/irda/nsc-ircc.c
index 05bfc98..51ca89c 100644
--- a/drivers/net/irda/nsc-ircc.c
+++ b/drivers/net/irda/nsc-ircc.c
@@ -1365,7 +1365,7 @@
 	
 	self = netdev_priv(dev);
 
-	IRDA_ASSERT(self != NULL, return 0;);
+	IRDA_ASSERT(self != NULL, return NETDEV_TX_OK;);
 
 	iobase = self->io.fir_base;