ath9k_hw: start noisefloor calibration after MCI reset

noisefloor calibration has to be loaded and started after
chip reset completion and restoring chainmask. Right now it is
being started before MCI reset completion on full reset. Fix that.

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