boards/x86/acrn: Add APIC IDs

The ACRN hypervisor uses 0, 2, 4, 6 as its local APIC IDs for
virtualized CPUs and not the 0, 1, 2, 3 defaults we have.

(I hate this feature, having to manually (!) probe and code these
things in C isn't scaling.  Zephyr needs to do the probing on its own
somehow, even if it's an offline tool in Linux or something.)

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>