platform/x86: hp-wmi: implement fan keep-alive

platform/x86: hp-wmi: implement fan keep-alive

The firmware on some HP laptops automatically reverts the fan speed
control to "Auto" mode after a 120 second timeout window.

To ensure that the user-selected fan profile (Max/Manual) persists,
implement a keep-alive mechanism that periodically refreshes the fan
mode trigger before the timeout occurs.

- Introduce a delayed workqueue to trigger the fan mode refresh every 90
  seconds, ensuring the system maintains the correct fan mode setting.
- Integrate the refresh mechanism into hp_wmi_apply_fan_settings() to
  start, update or cancel the keep-alive process based on the current
  fan mode.

This ensures that the driver stays in sync with the hardware.

Tested on: HP Omen 16-wf1xxx (board ID 8C78)

Signed-off-by: Krishna Chomal <krishna.chomal108@gmail.com>
Link: https://patch.msgid.link/20260113123738.222244-4-krishna.chomal108@gmail.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>