- Add a new structure type for the ACPI 3.0 SMAP entry that includes the
  optional attributes field.
- Add a 'machdep.smap' sysctl that exports the SMAP table of the running
  system as an array of the ACPI 3.0 structure.  (On older systems, the
  attributes are given a value of zero.)  Note that the sysctl only
  exports the SMAP table if it is available via the metadata passed from
  the loader to the kernel.  If an SMAP is not available, an empty array
  is returned.
- Add a format handler for the ACPI 3.0 SMAP structure to the sysctl(8)
  binary to format the SMAP structures in a readable format similar to
  the format found in boot messages.

MFC after:	2 weeks


git-svn-id: svn+ssh://svn.freebsd.org/base/head@270828 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f