ath9k: pass the ieee80211_hw on radio enable/disable

We use the ieee80211_hw for radio enable/disable but the wrong
structure hw was being used in consideration for virtual wiphys
as each virtual wiphy has its own ieee80211_hw struct.

Just pass the hw struct to ensure we use the right one. This should
fix the hw used and passed for radio enable/disable. This includes
the stoping / starting of the software TX queues so mac80211 doesn't
send us data for a specific virtual wiphy. ath9k already takes care
of pausing virtual wiphys and stopping the respective queues on its
own, but this should handle the idle mac80211 conf calls as well.

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