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/rtl8169.c b/drivers/net/rtl8169.c
index 1d7f31c..57ccbd9 100644
--- a/drivers/net/rtl8169.c
+++ b/drivers/net/rtl8169.c
@@ -624,7 +624,7 @@
 /**************************************************************************
 RESET - Finish setting up the ethernet interface
 ***************************************************************************/
-static void rtl_reset(struct eth_device *dev, bd_t *bis)
+static int rtl_reset(struct eth_device *dev, bd_t *bis)
 {
 	int i;
 
@@ -660,6 +660,7 @@
 #ifdef DEBUG_RTL8169
 	printf ("%s elapsed time : %d\n", __FUNCTION__, currticks()-stime);
 #endif
+	return 0;
 }
 
 /**************************************************************************