ath9k: Fix regulatory compliance

To comply with ETSI regulations, make sure that
the CCA registers are programmed with the threshold
values from the EEPROM/Caldata. A new field is used
to indicate if the card has been calibrated with the
required threshold information.

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