docs/zh_CN: add vm hugetlbfs_reserv translation

Translate .../vm/hugetlbfs_reserv.rst into Chinese.
Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Alex Shi <alexs@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/translations/zh_CN/vm/index.rst

@@ -29,6 +29,7 @@ TODO:待引用文档集被翻译完毕后请及时修改此处）
    ksm
    frontswap
    hwpoison
+   hugetlbfs_reserv
    memory-model
    mmu_notifier
    overcommit-accounting