* Synchronize the code of the rt mart branch to the master branch.
  * TTY device
  * Add lwP code from rt-smart
  * Add vnode in DFS, but DFS will be re-write for rt-smart
  * There are three libcpu for rt-smart:
    * arm/cortex-a, arm/aarch64
    * riscv64
Co-authored-by: NRbb666 <zhangbingru@rt-thread.com>
Co-authored-by: Nzhkag <zhkag@foxmail.com>

* [add] 新增README文档说明

瑞萨RA6M4开发板对segger_rtt使用通知

* Update README.md
Co-authored-by: Man, Jianting (Meco) <920369182@qq.com>

* [renesas/ra2l1-cpk] add Captouch板载触摸按键配置说明.md

* Update Captouch板载触摸按键配置说明.md

* [renesas/drv_wdt.c] Fix error code issues
[renesas/drv_i2c.c] add hardware i2c driver

* [update] drv_wdt.c,drv_i2c.c
Co-authored-by: Man, Jianting (Meco) <920369182@qq.com>

- 添加 RA 系列 BSP 开发教程
  - 添加 ra6m4-iot PPP 上网
  - 整理 驱动文件