mm/dynamic_hugetlb: support dynamic hugetlb on arm64

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I6XOIE


CVE: NA

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To support dynamic hugetlb on arm64, we need to do two more things. The
first one is to fix kabi broken in mem_cgroup, we use kabi_reserve_5 to
fix it in previous patch. The second one is to check cont-bit hugetlb
since this feature only support for PMD-size and PUD-size hugepage.

This feature only support for 4KB pagesize, not support for 16KB and 64KB.

Signed-off-by: Liu Shixin <liushixin2@huawei.com>