Sync ACPICA with Intel's version 20151124.

Sync ACPICA with Intel's version 20151124.

* Silence warnings about non-existant _Sx methods because they are
  optional. In fact, we already had a fix for this from sephe
  (671882eba43).

* Fixed bugs in FADT handling and auto-serialization.

* Removed support for _SUB in AcpiGetObjectInfo because it caused
  errors due to not fully initialized operation regions.

* Fixed issues with terminate/quit/exit commands in the debugger.
  Also thread ID support was added to the debugger.

* Allow multiple definitions blocks in ASL/AML files for iasl,
  acpiexec and acpixtract.

* Enhanced type checking for Name() in iasl. Also indent fixes for
  -ic and -ia.

* Additional error message for attempting to open a Scope() on an
  object defined in an SSDT.

* Improved formatting.

For a more detailed list, please see sys/contrib/dev/acpica/changes.txt.