livepatch/core: Split livepatch consistency

euler inclusion
category: feature
bugzilla: 51921
CVE: N/A

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In the previous version we forced the association between
livepatch wo_ftrace and stop_machine. This is unwise and
obviously confusing.

commit d83a7cb3 ("livepatch: change to a per-task
consistency model") introduce a PER-TASK consistency model.
It's a hybrid of kGraft and kpatch: it uses kGraft's per-task
consistency and syscall barrier switching combined with
kpatch's stack trace switching. There are also a number of
fallback options which make it quite flexible.

So we split livepatch consistency for without ftrace to two model:
[1] PER-TASK consistency model.
per-task consistency and syscall barrier switching combined with
kpatch's stack trace switching.

[2] STOP-MACHINE consistency model.
stop-machine consistency and kpatch's stack trace switching.

Signed-off-by: Cheng Jian <cj.chengjian@huawei.com>
Reviewed-by: Li Bin <huawei.libin@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>

Signed-off-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
Signed-off-by: Dong Kai <dongkai11@huawei.com>

Signed-off-by: Ye Weihua <yeweihua4@huawei.com>
Reviewed-by: Yang Jihong <yangjihong1@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>