MFC 235024,235029,235556,235834,235845:

MFC 235024,235029,235556,235834,235845:
Use MADT to match ACPI Processor objects to CPUs.  MADT and DSDT/SSDTs may
list CPUs in different orders, especially for disabled logical cores.  Now
we match ACPI IDs from the MADT with Processor objects, strictly order CPUs
accordingly, and ignore disabled cores.  This prevents us from executing
methods for other CPUs, e. g., _PSS for disabled logical core, which may not
exist.  Unfortunately, it is known that there are a few systems with buggy
BIOSes that do not have unique ACPI IDs for MADT and Processor objects.  To
work around these problems, 'debug.acpi.cpu_unordered' tunable is added.
Set this to a non-zero value to restore the old behavior.

git-svn-id: svn://svn.freebsd.org/base/stable/9@237822 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f