docs/zh_CN: add dt changesets translation

Translate .../devicetree/changesets.rst into Chinese.

Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Alex Shi <alexs@kernel.org>
Link: https://lore.kernel.org/r/07d23cedda1e2cd8cf40d68059024d116f8d004e.1662449105.git.siyanteng@loongson.cn


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