platform/x86: wmi: Update documentation of WCxx/WExx ACPI methods

Inform potential firmware developers that WExx ACPI methods are
always called by the WMI driver core even if the associated WMI event
is not marked as being expensive.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20250619221440.6737-2-W_Armin@gmx.de


Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>