docs/zh_CN: Update the translation of page_owner to 6.0-rc7

1)Update to commit 8f0efa81 ("mm/page_owner.c: add
llseek for page_owner")

2)Translate some words into Chinese.

Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Alex Shi <alexs@kernel.org>
Link: https://lore.kernel.org/r/52bc8df87618af951b34759487f05775416cb4d4.1664360331.git.siyanteng@loongson.cn


Signed-off-by: Jonathan Corbet <corbet@lwn.net>