ath9k: disable radio when all devices are marked idle

This uses the new configuration changes indicated up by
mac80211 when all interfaces are marked idle. We need to do
a little more work as we have our own set of virtual
wiphys within ath9k.

Only when all virtual wiphys are inactive do we allow an idle
state change for a wiphy to trigger disabling the radio.

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/ath9k.h

@@ -691,6 +691,7 @@ void ath9k_wiphy_pause_all_forced(struct ath_softc *sc,
 				  struct ath_wiphy *selected);
 bool ath9k_wiphy_scanning(struct ath_softc *sc);
 void ath9k_wiphy_work(struct work_struct *work);
+bool ath9k_all_wiphys_idle(struct ath_softc *sc);
 
 void ath9k_iowrite32(struct ath_hw *ah, u32 reg_offset, u32 val);
 unsigned int ath9k_ioread32(struct ath_hw *ah, u32 reg_offset);