ACPICA stub mechanisms

This branch includes 2 commits to remove the untested stub commits and 7 commits whose linuxized ones have already been sent to linux acpi mailing list and have been merged by linux-pm/bleeding-edge branch.
The 7 commits have already been tested in bleeding-edge branch of linux-pm repo.
For ACPICA, these patches introduce no functional changes and almost no-ops.

These patches provide required mechanisms for OSPMs to implement stubbed ACPICA header which is required by Linux.  It is tested and detected that <linux/sfi_acpi.h> requires ACPICA to offer stub capability for Linux to sort wrong inclusions out.