The hardcoded APIC ID will be kept as default if the CPU is not found in
ACPI MADT.
Note that ACPI may expose more "CPUs" than there actually are
physically. Thus, make the logic aware of this possibility by checking
the enabled flas. (Non-enabled CPU are ignored).
This fixes up_squared board made of Celeron CPU.
Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>