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/sun3_82586.c b/drivers/net/sun3_82586.c
index a39c0b9..7bb2742 100644
--- a/drivers/net/sun3_82586.c
+++ b/drivers/net/sun3_82586.c
@@ -1023,7 +1023,7 @@
 #if(NUM_XMIT_BUFFS > 1)
 	if(test_and_set_bit(0,(void *) &p->lock)) {
 		printk("%s: Queue was locked\n",dev->name);
-		return 1;
+		return NETDEV_TX_BUSY;
 	}
 	else
 #endif