bcmpcie_mdio_read
int bcmpcie_mdio_read(struct bcmpcie_softc *sc, uint8_t, uint16_t,
error = bcmpcie_mdio_read(sc, 0, MDIO_SSC_CNTL, ®);
error = bcmpcie_mdio_read(sc, 0, MDIO_SSC_STATUS, ®);