passthru_get_mmio
gsm = passthru_get_mmio(sc, GVT_D_MAP_GSM);
vbt = passthru_get_mmio(sc, GVT_D_MAP_VBT);
opregion = passthru_get_mmio(sc, GVT_D_MAP_OPREGION);
opregion = passthru_get_mmio(sc, GVT_D_MAP_OPREGION);
struct passthru_mmio_mapping *passthru_get_mmio(struct passthru_softc *sc,