platform/x86: int3472: discrete: Use FIELD_GET() on the GPIO _DSM return value

Add defines for the various fields encoded in the GPIO _DSM integer
return value and then use FIELD_GET() to get field values.

Suggested-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230616172132.37859-6-hdegoede@redhat.com