ath9k/ath9k_htc: Fix PS wrappers for RF kill

ath9k_hw_gpio_get reads the GPIO in/out registers to get the status of
GPIO pins, so use PS wrappers

Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>