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/de600.c b/drivers/net/de600.c
index c866ca9..e1af089 100644
--- a/drivers/net/de600.c
+++ b/drivers/net/de600.c
@@ -168,14 +168,14 @@
 	if (free_tx_pages <= 0) {	/* Do timeouts, to avoid hangs. */
 		tickssofar = jiffies - dev->trans_start;
 		if (tickssofar < 5)
-			return 1;
+			return NETDEV_TX_BUSY;
 		/* else */
 		printk(KERN_WARNING "%s: transmit timed out (%d), %s?\n", dev->name, tickssofar, "network cable problem");
 		/* Restart the adapter. */
 		spin_lock_irqsave(&de600_lock, flags);
 		if (adapter_init(dev)) {
 			spin_unlock_irqrestore(&de600_lock, flags);
-			return 1;
+			return NETDEV_TX_BUSY;
 		}
 		spin_unlock_irqrestore(&de600_lock, flags);
 	}
@@ -199,7 +199,7 @@
 		if (was_down || (de600_read_byte(READ_DATA, dev) != 0xde)) {
 			if (adapter_init(dev)) {
 				spin_unlock_irqrestore(&de600_lock, flags);
-				return 1;
+				return NETDEV_TX_BUSY;
 			}
 		}
 	}