MAINTAINERS: add reviewer for Chinese translations

MAINTAINERS: add reviewer for Chinese translations

Dongliang Mu has translated a substantial portion of kernel documentation
into Chinese, developed scripts/checktransupdate.py utility to automate
tracking of translated content updates, and actively reviewed patches.

Thus, add Dongliang Mu as a reviewer for the translations of
Chinese Documentation.

Signed-off-by: Dongliang Mu <dzm91@hust.edu.cn>
Reviewed-by: Alex Shi <alexs@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250217043109.3571459-1-dzm91@hust.edu.cn