platform/x86: oxpec: Add turbo led support to X1 devices

platform/x86: oxpec: Add turbo led support to X1 devices

The X1 and X1 mini lineups feature an LED nested within their turbo
button. When turbo takeover is not enabled, the turbo button allows
the device to switch from 18W to 25W TDP. When the device is in the
25W TDP mode, the LED is turned on.

However, when we engage turbo takeover, the turbo led remains on its
last state, which might be illuminated and cannot be currently
controlled. Therefore, add the register that controls it under sysfs,
to allow userspace to turn it off once engaging turbo takeover and then
control it as they wish.

2024 OneXPlayer devices, other than the X1s, do not have a turbo LED.
However, earlier models do, so this can be extended to them as well
when the register for it is found.

Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Derek J. Clark <derekjohn.clark@gmail.com>
Signed-off-by: Antheas Kapenekakis <lkml@antheas.dev>
Link: https://lore.kernel.org/r/20250425111821.88746-8-lkml@antheas.dev
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>