ath10k: release pre_cal_file while unloading driver

Failing to release pre_cal_file caldata on deinit causes memory leak.

Fixes: b131129d ("ath10k: fix calibration init sequence of qca99x0")
Signed-off-by: Rajkumar Manoharan <rmanohar@qti.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>