mac80211: ath9k: enable access to GPIO

Enable access to GPIO chip and its pins for Atheros AR92xx
wireless devices. For now AR9285 and AR9287 are supported.

Signed-off-by: Michal Cieslakiewicz <michal.cieslakiewicz@wp.pl>
Acked-by: Hartmut Knaack <knaack.h@gmx.de>

SVN-Revision: 48881