ath9k_hw: rename mrcCCKOff to fix smatch warning

Rename mrcCCKOff for better code readability and also fixes
the smatch warning.

drivers/net/wireless/ath/ath9k/ar9003_phy.c:982
	ar9003_hw_ani_control() Error invalid range 1 to 0.

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