is reserved by the loader, and thus any tunable name with that suffix will
be silently discarded.
Document this in the header and man page so that other developers do not
develop so many bumps on the head after banging it against the wall.
Detective work by: Mark Santcroos, grehan
* AcpiOsDerivePciId(): finds a bus number, given the slot/func and the
acpi parse tree.
* AcpiOsPredefinedOverride(): use the sysctl hw.acpi.os_name to
override the value for _OS.
Ideas from: takawata, jhb
Reviewed by: takawata, marcel
Tested on: i386, ia64