docs/zh_CN: correct regi_chg(),regi_add() to region_chg(),region_add()

Minor typo fix in translations.

Signed-off-by: Xueshi Hu <xueshi.hu@smartx.com>
Acked-by: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20230813132417.815036-1-xueshi.hu@smartx.com