mm: add support for page cache use reliable memory

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4PM0Z


CVE: NA

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__page_cache_alloc is used to alloc page cache in most file system,
such as ext4, f2fs, so add GFP_RELIABLE flag to use reliable
memory when alloc page cache.

Signed-off-by: Chen Wandun <chenwandun@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>