ACPICA: FADT: set acpi_gbl_use_default_register_widths to TRUE by default

This returns the FADT support to the original behavior, which is
to use default register widths. However, now check each register
definition and report a warning if it differs from the default.
This is a first step to moving away from the default widths,
rather than outright believing the widths in all FADTs for all
machines, considered rather dangerous until more data is obtained.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>