During the board's device_init we can configure the first
MAC for fixed_link by calling:
- fixed_phy_add(PHY_POLL, 1, &stmmac0_fixed_phy_status));)
+ fixed_phy_add(PHY_POLL, 1, &stmmac0_fixed_phy_status, -1);
and the second one, with a real PHY device attached to the bus,
by using the stmmac_mdio_bus_data structure (to provide the id, the
reset procedure etc).