mac_init
sc->sc_ops.mac_init(sc->sc_ops.cookie);
void (*mac_init)(void *);
sc->sc_sc.sc_ops.mac_init = rtwn_mac_init;
sc->sc_sc.sc_ops.mac_init = urtwn_mac_init;
int mac_init(struct sshmac *);
if ((r = mac_init(mac)) != 0)