Doesn't do much but provided the detection path for it and ability to
hold initialized state. The higher level platform code is going to need
to use it directly so will mostly just provide an api for access to it.
Moved ACPI sniffing back to just after the VM is initialized instead of
all the way into platform_init(). This should try to ensure that all
drivers that come up afterwards will have ioapics discovered in case
future development tries to enable and use them, kicking the machine out
of virtual-wire-mode.
936ee8ac81