docs/zh_CN: add admin-guide damon start translation

Translate Documentation/admin-guide/mm/damon/start.rst into Chinese.

Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Alex Shi <alexs@kernel.org>
Link: https://lore.kernel.org/r/e6e328be018cbf5f9105adfdad56c951acbb8c8f.1646899089.git.siyanteng@loongson.cn


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