acpi_cpu: Make device unit numbers match OS CPU IDs.
There are already APIC ID, ACPI ID and OS ID for each CPU. In perfect world all of those may match, but at least for SuperMicro server boards none of them do. Plus none of them match the CPU devices listing order by ACPI. Previous code used the ACPI device listing order to number cpuX devices. It looked nice from NewBus perspective, but introduced 4th different set of IDs. Extremely confusing one, since in some places the device unit numbers were treated as OS CPU IDs (coretemp), but not in others (sysctl dev.cpu.X.%location).