struct AlignedFacs

According to the the ACPI specification, section 5.2.10, the platform boot firmware aligns

the FACS (Firmware ACPI Control Structure) on a 64-byte boundary anywhere within the system’s

memory address space. This means we can assume the alignment when interacting with it.

Specifically we need to be able to manipulate the GlobalLock contained in the FACS table with

atomic operations, and these require aligned accesses.

Although we know that the table will be aligned, to prevent the compiler from complaining we

use a wrapper struct to set the alignment attribute.