ath9k: Fix redundant PS wrappers

Move the PowerSave wrappers outside ath_paprd_activate(),
since they are already being used in ath_paprd_calibrate().

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