ACPICA: ACPI 4.0 : Add new return package type, restructure module.

Added one new package type, a package that contains a revision number and
a variable number of sub-packages. Restructured the module to
put the sub-package list traversal in a separate function.

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>