Documentation/Intel: Add ACPI link and more FADT documentation

Add a link to the ACPI specification.
Update the FADT table to better describe the use and ACPI specification
reference for the various fields.

TEST=None

Change-Id: I77cd925800d71398be6d677de48874099ea26479
Signed-off-by: Lee Leahy <leroy.p.leahy@intel.com>
Reviewed-on: https://review.coreboot.org/13765
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <martinroth@google.com>
2 files changed