i386/cpu: Consolidate die-id validity in smp context

i386/cpu: Consolidate die-id validity in smp context

The field die_id (default as 0) and has_die_id are introduced to X86CPU.
Following the legacy smp check rules, the die_id validity is added to
the same contexts as leagcy smp variables such as hmp_hotpluggable_cpus(),
machine_set_cpu_numa_node(), cpu_slot_to_string() and pc_cpu_pre_plug().

Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Message-Id: <20190612084104.34984-4-like.xu@linux.intel.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>