net: Add option to disable fiber on M88E1111 PHY for PPC4xx

By defining CONFIG_M88E1111_DISABLE_FIBER boards can configure the
M88E1111 PYH to disable fiber. This is needed for an upcoming PPC460GT
based board, which has fiber/copper auto-selection enabled by default.
This doesn't seem to work. So we disable fiber in the PHY register.

Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: Ben Warren <biggerbadderben@gmail.com>

drivers/net/4xx_enet.c

@@ -1095,6 +1095,11 @@ static int ppc_4xx_eth_init (struct eth_device *dev, bd_t * bis)
 		miiphy_write (dev->name, reg, 0x18, 0x4101);
 		miiphy_write (dev->name, reg, 0x09, 0x0e00);
 		miiphy_write (dev->name, reg, 0x04, 0x01e1);
+#if defined(CONFIG_M88E1111_DISABLE_FIBER)
+		miiphy_read(dev->name, reg, 0x1b, &reg_short);
+		reg_short |= 0x8000;
+		miiphy_write(dev->name, reg, 0x1b, reg_short);
+#endif
 #endif
 #if defined(CONFIG_M88E1112_PHY)
 		if (bis->bi_phymode[devnum] == BI_PHYMODE_SGMII) {