hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4UAQ1

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Introduce 'arch_klp_save_old_code' preparing for moving func_node
initializing codes out of stop_machine.
Signed-off-by: NZheng Yejian <zhengyejian1@huawei.com>
Reviewed-by: NKuohai Xu <xukuohai@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>