phy: Change mii_bus id field to a string

Having the id field be an int was making more complex bus topologies
excessively difficult.  For now, just convert it to a string, and
change all instances of "bus->id = val" to
snprintf(id, MII_BUS_ID_LEN, "%x", val).

Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/arch/powerpc/platforms/pasemi/gpio_mdio.c b/arch/powerpc/platforms/pasemi/gpio_mdio.c
index b465429..ab69554 100644
--- a/arch/powerpc/platforms/pasemi/gpio_mdio.c
+++ b/arch/powerpc/platforms/pasemi/gpio_mdio.c
@@ -241,7 +241,7 @@
 	new_bus->reset = &gpio_mdio_reset;
 
 	prop = of_get_property(np, "reg", NULL);
-	new_bus->id = *prop;
+	snprintf(new_bus->id, MII_BUS_ID_SIZE, "%x", *prop);
 	new_bus->priv = priv;
 
 	new_bus->phy_mask = 0;