ath9k_hw: Enable manual peak calibration for AR9485

Manual peak calibration is currently enabled only for
AR9462 and AR9565. This is also required for AR9485.
The initvals are also modified to disable HW peak calibration.

Cc: <stable@vger.kernel.org>
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>