ath9k: Update AR955x initvals

* Fix a 11b/EVM issue by adjusting
  FIR filter coefficients.

* Fix a problem with receiving probe request
  frames sent at 11b rate.

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