* [lwip-2.1.2] improve lwipopts.h

* 增加LWIP RTT侧版本定义

* 移动调整cc.h和lwipopts.h定义

* lwip2.1.2 2.0.3抽出lwipopts.h lwippools.h

* remove lwip1.4.1 lwipopts.h

* [update] modify the default config through v1.4.1

* delete the useless macro and modify some unclear comments.

* [lwipopts.h] 完善头文件相关宏以及临界区保护相关宏

* remove latest version label
Co-authored-by: Nliuxianliang <liuxianliang@rt-thread.com>