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/eepro100.c b/drivers/net/eepro100.c
index 738146e..96ed271 100644
--- a/drivers/net/eepro100.c
+++ b/drivers/net/eepro100.c
@@ -485,7 +485,7 @@
 
 static int eepro100_init (struct eth_device *dev, bd_t * bis)
 {
-	int i, status = 0;
+	int i, status = -1;
 	int tx_cur;
 	struct descriptor *ias_cmd, *cfg_cmd;
 
@@ -598,7 +598,7 @@
 		goto Done;
 	}
 
-	status = 1;
+	status = 0;
 
   Done:
 	return status;