ACPI: fan: Use ACPI handle when retrieving _FST

ACPI: fan: Use ACPI handle when retrieving _FST

Usage of the ACPI device should be phased out in the future, as
the driver itself is now using the platform bus.

Replace any usage of struct acpi_device in acpi_fan_get_fst() to
allow users to drop usage of struct acpi_device.

Also extend the integer check to all three package elements.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://patch.msgid.link/20251007234149.2769-2-W_Armin@gmx.de
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>