memcg: Export memory.events{local} from cgroupv2 to cgroupv1

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8JVN0



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Export "memory.events" and "memory.events.local" from cgroupv2 to
cgroupv1.

There are some differences between v2 and v1:

1)events of MEMCG_OOM_GROUP_KILL is not included in cgroupv1. Because,
there is no member of memory.oom.group.

2)events of MEMCG_MAX is represented with "limit_in_bytes" in cgroupv1
instead of memory.max

3)event of oom_kill is include in memory.oom_control. oom_kill only show
the local cgroup event. Therfore, when CONFIG_MEMCG_V1_RECLAIM=y, use
memory_events_local instead of memory_events.

4)enable memory_events contain sub cgroups' counts in cgroupv1.

Signed-off-by: Lu Jialin <lujialin4@huawei.com>