ACPICA: Add support for module-level executable AML code

Add limited support for executable AML code that exists outside
of any control method. This type of code has been illegal since
ACPI 2.0.  The code must exist in an If/Else/While block. All AML
tables are supported, including tables that are dynamically loaded.
ACPICA BZ 762.

http://acpica.org/bugzilla/show_bug.cgi?id=762

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