ath10k: add debugfs file warm_hw_reset

ath10k: add debugfs file warm_hw_reset

Debugfs support to do hardware warm reset with WMI command
WMI_PDEV_PARAM_PDEV_RESET for 10.4 and 10.2.4(if wmi
service is enabled in the firmware for backward compatibility).

This change is purely for debugging purpose when hardware hangs/mutes.

This hardware reset won't affect the connectivity but there will be small
pause in data traffic. Here we are doing BB/MAC level reset and hence
whenever the BB/MAC watchdog is triggered, it does a hardware_chip_reset.
So the target will be in the active state.

Below command used to warm reset the hardware.
echo 1 > /sys/kernel/debug/ieee80211/phyX/ath10k/warm_hw_reset

Tested in QCA988X with firmware ver 10.2.4.70.45
Tested in QCA4019 with firmware ver 10.4-3.2.1.1-00011

Signed-off-by: Maharaja Kennadyrajan <mkenna@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>