Make the Samsung Galaxy Book4 Edge (x1e80100) boot in ACPI mode;

Make the Samsung Galaxy Book4 Edge (x1e80100) boot in ACPI mode;
Until now the kernel did panic during early boot because we couldn't
respond to the battery requests sent to the 0xa1 "bus".  This (dummy)
driver registers a 0xa1 region space very early, and responds with a
static zero value to satisfy the battery requests on 0xa1, which let us
boot successfully to multi-user.

In the future this machine should be operated in FDT mode, and an improved
AML parsing interface might make this workaround obsolete also for RAMDISK.

Help and OK kettenis@, deraadt@