mm/dynamic_pool: add restore_pool ops to reclaim memory and restore hugepages

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8S9BY


CVE: NA

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Before destroy a dynamic pool, make sure all memory are freed and all
split hugepages are restored.

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