MAINTAINERS: Become the docs/zh_CN maintainer

It's time to become a maintainer of Chinese documentation, and Yanteng's plan
is to help everyone with the utmost enthusiasm and patience.
Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Alex Shi <alexs@kernel.org>
Link: https://lore.kernel.org/r/b0c1324d1d63846d700ab354446a6deaf30754c0.1652712771.git.siyanteng@loongson.cnSigned-off-by: Jonathan Corbet <corbet@lwn.net>

MAINTAINERS

@@ -4615,6 +4615,7 @@ F:	Documentation/dev-tools/checkpatch.rst
 
 CHINESE DOCUMENTATION
 M:	Alex Shi <alexs@kernel.org>
+M:	Yanteng Si <siyanteng@loongson.cn>
 S:	Maintained
 F:	Documentation/translations/zh_CN/