ath9k_hw: Fix number of GPIO pins for AR9287/9300

ath9k_hw: Fix number of GPIO pins for AR9287/9300

commit 6321eb0977b011ac61dfca36e7c69b2c4325b104 upstream.

this patch fixes the assumption of maximum number of GPIO pins present
in AR9287/AR9300. this fix is essential as we might encounter some
functionality issues involved in accessing the status of GPIO pins which
are all incorrectly assumed to be not within the range of max_num_gpio
of AR9300/AR9287 chipsets

Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>