All the CPU hotplug facilities are ready. Assemble them
to start up CPU hot-plug capability for arm/virt.
This also adds CPU cold plug support to arm virt machine
board. CPU cold plug means adding CPU by using "-device
xx-arm-cpu" when we bring up Qemu.
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
(cherry picked from commit d5d118431a64c4202cb28c27bdea0f8667beb5dd)
