boards: get mac address from environment

The boards that get converted here to use the environment for the mac
address rather than global data:
	debris
	mgcoge
	mgsuvd
	muas3001
	netstal
	pn62
	sixnet
	vcma9
	xilinx (the ones that use xilinx_enet)

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
CC: Ben Warren <biggerbadderben@gmail.com>
CC: Sangmoon Kim <dogoil@etinsys.com>
CC: Heiko Schocher <hs@denx.de>
CC: David Mueller <d.mueller@elsoft.ch>
CC: Niklaus Giger <niklaus.giger@netstal.com>
CC: Wolfgang Grandegger <wg@denx.de>
CC: Dave Ellis <DGE@sixnetio.com>
CC: Ricardo Ribalda <ricardo.ribalda@uam.es>
diff --git a/board/pn62/pn62.c b/board/pn62/pn62.c
index 1b545bf..53d7e57 100644
--- a/board/pn62/pn62.c
+++ b/board/pn62/pn62.c
@@ -30,7 +30,7 @@
 DECLARE_GLOBAL_DATA_PTR;
 
 static int get_serial_number (char *string, int size);
-static int get_mac_address (int id, u8 * mac, char *string, int size);
+static void get_mac_address(int id, u8 *mac);
 
 #ifdef CONFIG_SHOW_BOOT_PROGRESS
 void show_boot_progress (int phase)
@@ -138,18 +138,16 @@
 	}
 	show_startup_phase (9);
 
-	if (getenv ("ethaddr") == NULL &&
-		get_mac_address (0, mac, str, sizeof (str)) > 0) {
-		setenv ("ethaddr", str);
-		memcpy (gd->bd->bi_enetaddr, mac, 6);
+	if (!eth_getenv_enetaddr("ethaddr", mac)) {
+		get_mac_address(0, mac);
+		eth_setenv_enetaddr("ethaddr", mac);
 	}
 	show_startup_phase (10);
 
 #ifdef CONFIG_HAS_ETH1
-	if (getenv ("eth1addr") == NULL &&
-		get_mac_address (1, mac, str, sizeof (str)) > 0) {
-		setenv ("eth1addr", str);
-		memcpy (gd->bd->bi_enet1addr, mac, 6);
+	if (!eth_getenv_enetaddr("eth1addr", mac)) {
+		get_mac_address(1, mac);
+		eth_setenv_enetaddr("eth1addr", mac);
 	}
 #endif /* CONFIG_HAS_ETH1 */
 	show_startup_phase (11);
@@ -177,15 +175,9 @@
 	return i;
 }
 
-static int get_mac_address (int id, u8 * mac, char *string, int size)
+static void get_mac_address(int id, u8 *mac)
 {
-	if (size < 6 * 3)
-		return -1;
-
 	i2155x_read_vpd (I2155X_VPD_MAC0_START + 6 * id, 6, mac);
-	return sprintf (string, "%02x:%02x:%02x:%02x:%02x:%02x",
-				mac[0], mac[1], mac[2],
-				mac[3], mac[4], mac[5]);
 }
 
 int board_eth_init(bd_t *bis)