target/loongarch: cpu: Implement get_arch_id callback

Implement the callback for getting the architecture-dependent CPU
ID, the cpu ID is physical id described in ACPI MADT table, this
will be used for cpu hotplug.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Reviewed-by: Song Gao <gaosong@loongson.cn>
Message-Id: <20230824005007.2000525-1-maobibo@loongson.cn>
Signed-off-by: Song Gao <gaosong@loongson.cn>
3 files changed