Don't use cpu_index as apic_id.

Don't use cpu_index as apic_id.

(patch is on top of "Apic creation should not depend on pci" series)

Currently cpu_index is used as cpu apic id on x86.  This is incorrect
since apic ids not have to be continuous (they can also encode cpu
hierarchy information). This patch uses cpuid_apic_id for initial apic id
value. For now cpuid_apic_id is set to be equal to cpu_index so behaviour
is fully backward compatible, but it allows us to add qemu option to
provide other values for cpu apic id.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>