ath9k: Program correct initvals for FCC

* CUS217 specific initvals have to be programmed.
* iniAdditional is not used for AR9462/AR9565, remove it.
* Handle channel 2484 for regulatory compliance.

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