ath9k: Fix LNA gpio for AR9485

The commit "ath9k: Add custom parameters for CUS198" didn't
pass the correct gpio value to ath9k_hw_cfg_output(). Fix it.

Reported-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>