mm/ksm: Remove the ksm_merge_any status

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7R48G



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Remove the ksm_merge_any status, as the ksm status of processes within
the same cgroup may not be consistent, since the prctl interface can also
change the ksm status of a process. Therefore, the ksm_merge_any status
may not always represent the ksm status of all processes within a cgroup.
Remove it.

Signed-off-by: Longlong Xia <xialonglong1@huawei.com>