tulip_mii_writereg
static void tulip_mii_writereg(tulip_softc_t *, u_int, u_int, u_int);
tulip_mii_writereg(sc, phyaddr, PHYREG_CONTROL, PHYCTL_RESET);
tulip_mii_writereg(sc, phyaddr, PHYREG_AUTONEG_ADVERTISEMENT, (status >> 6) | 0x01);
tulip_mii_writereg(sc, phyaddr, PHYREG_CONTROL, data|PHYCTL_AUTONEG_RESTART|PHYCTL_AUTONEG_ENABLE);
tulip_mii_writereg(sc, sc->tulip_phyaddr, PHYREG_CONTROL, data);