pc: acpi: consolidate legacy CPU hotplug in one file

pc: acpi: consolidate legacy CPU hotplug in one file

Since AML part of CPU hotplug is tightly coupled with
its hardware part (IO port layout/protocol), move
build_legacy_cpu_hotplug_aml() to cpu_hotplug.c
and remove empty cpu_hotplug_acpi_table.c

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Marcel Apfelbaum <marcel@redhat.com>