wpi_power_group
struct wpi_power_group *group = &sc->groups[n];
struct wpi_power_group *, struct ieee80211_channel *, int);
struct wpi_power_group *group;
wpi_get_power_index(struct wpi_softc *sc, struct wpi_power_group *group,
struct wpi_power_group groups[WPI_POWER_GROUPS_COUNT];