ACPICA: Hardcode access width for the reset register.

The ACPI spec requires the reset register width to be 8, so we
now hardcode it and ignore the FADT value. This provides/maintains
compatibility with other ACPI implementations that have allowed
BIOS code with bad register width values to go unnoticed.
Matthew Garett, Bob Moore, Lv Zheng.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>