platform/x86: x86-android-tablets: Move core code into new core.c file

Move the helpers to get IRQs + GPIOs as well as the core code for
instantiating all the devices missing from ACPI into a new core.c file.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20230301092331.7038-4-hdegoede@redhat.com