ath9k: Update AR955x initvals

This patch disables HW peak detect calibration for
AR955x, since it is problematic on a few boards.
Instead, manual calibration will be done in the
driver.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>