Fix Ethernet init() return codes

Change return values of init() functions in all Ethernet drivers to conform
to the following:

    >=0: Success
    <0:  Failure

All drivers going forward should return 0 on success.  Current drivers that
return 1 on success were left as-is to minimize changes.

Signed-off-by: Ben Warren <biggerbadderben@gmail.com>
Acked-by: Stefan Roese <sr@denx.de>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Kim Phillips <kim.phillips@freescale.com>
Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Acked-By: Timur Tabi <timur@freescale.com>
diff --git a/drivers/net/tsi108_eth.c b/drivers/net/tsi108_eth.c
index 524e9da..a09115e 100644
--- a/drivers/net/tsi108_eth.c
+++ b/drivers/net/tsi108_eth.c
@@ -792,7 +792,7 @@
 	    (dev->enetaddr[0] << 16);
 
 	if (marvell_88e_phy_config(dev, &speed, &duplex) == 0)
-		return 0;
+		return -1;
 
 	value =
 	    MAC_CONFIG_2_PREAMBLE_LENGTH(7) | MAC_CONFIG_2_PAD_CRC |
@@ -864,7 +864,7 @@
 	/* enable TX queue */
 	reg_TX_CONTROL(base) = TX_CONTROL_GO | 0x01;
 
-	return 1;
+	return 0;
 }
 
 /*