ath10k: add wmi support for pdev_set_quiet_mode

Add WMI support to send pdev_set_quiet_mode command to target.
This will be used for thermal mitigation purpose.

Signed-off-by: Rajkumar Manoharan <rmanohar@qti.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>