docs/zh_CN: update sparse translation

Sparse documents are too outdated,let's update sparse.rst to the latest version.

Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Alex Shi <alexs@kernel.org>
Link: https://lore.kernel.org/r/497c334954afc0190d5531716d273925baedfff2.1637565886.git.siyanteng@loongson.cn


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