emac_mii_readreg
mii->mii_readreg = emac_mii_readreg;
int emac_mii_readreg (device_t, int, int, uint16_t *);
static int emac_mii_readreg(device_t, int, int, uint16_t *);
mii->mii_readreg = emac_mii_readreg;