ath9k_hw: extend GPIO pin select mask for rfkill

this extends the bits for rf kill GPIO selection to [7:2] from [4:2] as
we use GPIO pin 11 as rfkill for AR9480 and also remove few unused
macros

Cc: Wilson Tsao <wtsao@qca.qualcomm.com>
Cc: "Hu, Russell" <rhu@qca.qualcomm.com>
Cc: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>