Synchronize a bunch of things from FreeBSD-5 in preparation for the new

Synchronize a bunch of things from FreeBSD-5 in preparation for the new
ACPICA driver support.

* Bring in a lot of new bus and pci DEV_METHODs from FreeBSD-5
* split apic.h into apicreg.h and apicio.h
* rename INTR_TYPE_FAST -> INTR_FAST and move the #define
* rename INTR_TYPE_EXCL -> INTR_EXCL and move the #define
* rename some PCIR_ registers and add additional macros from FreeBSD-5
* note: new pcib bus call, host_pcib_get_busno() imported.
* kern/subr_power.c no longer optional.

Other changes:

* machine/smp.h machine smp/smptests.h can now be #included unconditionally,
  and some APIC_IO vs SMP separation has been done as well.
* gd_acpi_id and gd_apic_id added to machine/globaldata.h prep for new
  ACPI code.

Despite all the changes, the generated code should be virtually the same.
These were mostly additions which the pre-existing code does not (yet) use.