ACPICA: Clear reserved fields for incoming ACPI 1.0 FADTs

Fixed a problem with the internal FADT conversion where ACPI 1.0
FADTs that contained invalid non-zero values in reserved fields
could cause later failures because these fields have meaning in
later revisions of the FADT. For incoming ACPI 1.0 FADTs, these
fields are now always zeroed. (Preferred_PM_Profile, PSTATE_CNT,
CST_CNT, IAPC_BOOT_FLAGS.)

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>