mm: Count reliable memory info based on zone info

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4SK3S


CVE: NA

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Count reliable memory info based on zone info. Any zone below
ZONE_MOVABLE is seed as reliable zone and sum the pages there.

Signed-off-by: Ma Wupeng <mawupeng1@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>