stand: bandaide for acpi

Old binaries do not set acpi.rsdp early enough. So when we boot with an
older loader.efi from an ESP that's not been updated, we assume there's
no ACPI on this system. This is unwise. Put a band-aide on this until we
can implement a proper 'feature' variable that the binary reports so we
can do conditionals for things like this in the future.

This is at best a rapid-response stop-gap.

Glanced at by: kevans
Sponsored by: Netflix