translate the "netif-msg.rst" into Simplified Chinese.
Update the translation through commit c4d5dff60f
("docs: networking: convert netif-msg.txt to ReST")
Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Signed-off-by: Jiang Kun <jiang.kun2@zte.com.cn>
Reviewed-by: Yanteng Si <siyanteng@cqsoftware.com.cn>
Signed-off-by: Alex Shi <alexs@kernel.org>
