net: use symbolic values for ndo_start_xmit() return codes

Convert magic values 1 and -1 to NETDEV_TX_BUSY and NETDEV_TX_LOCKED respectively.

0 (NETDEV_TX_OK) is not changed to keep the noise down, except in very few cases
where its in direct proximity to one of the other values.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/pcmcia/xirc2ps_cs.c b/drivers/net/pcmcia/xirc2ps_cs.c
index a3685c0..ef37d22 100644
--- a/drivers/net/pcmcia/xirc2ps_cs.c
+++ b/drivers/net/pcmcia/xirc2ps_cs.c
@@ -1399,7 +1399,7 @@
     DEBUG(2 + (okay ? 2 : 0), "%s: avail. tx space=%u%s\n",
 	  dev->name, freespace, okay ? " (okay)":" (not enough)");
     if (!okay) { /* not enough space */
-	return 1;  /* upper layer may decide to requeue this packet */
+	return NETDEV_TX_BUSY;  /* upper layer may decide to requeue this packet */
     }
     /* send the packet */
     PutWord(XIRCREG_EDP, (u_short)pktlen);