docs/zh_CN: fix indent issue in submitting-drivers

Tame 'make htmldocs' w/o indent complains.
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Harry Wei <harryxiyou@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Li Yang <leoyang.li@nxp.com>
Cc: TripleX Chung <xxx.phy@gmail.com>
Signed-off-by: Weiwei Jia <harryxiyou@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/translations/zh_CN/process/submitting-drivers.rst

@@ -137,9 +137,13 @@ Linux 设备驱动程序，第三版（探讨 2.6.10 版内核）：
 
 LWN.net:
 	每周内核开发活动摘要 - http://lwn.net/
+
 	2.6 版中 API 的变更：
+
 		http://lwn.net/Articles/2.6-kernel-api/
+
 	将旧版内核的驱动程序移植到 2.6 版：
+
 		http://lwn.net/Articles/driver-porting/
 
 内核新手(KernelNewbies):