Co-authored-by: 1516081466@qq.com <ws051000>

* [risc-v/libcpu] porting Smart & RTOS
* [fix] rv64 plic
* [risc-v/rv64] remove macro in rtdef

* fix usage of rt_event for drv_spi.c in renesas's libraries.

* add core-v-mcu bsp

* 规范bsp格式 添加readme

* 修改readme

Co-authored-by: 1516081466@qq.com <ws051000>

* add ra4m2 soc support, add sci spi support for ra4m2

* update ra4m2-eco/README.md

* update ra4m2-eco/README.md

* rename board picture name.

* reduce picture size, update README.md, remove file 'Target 1.bat'

* reduce picture size

* [tools][musl] add scons --exec-prefix= 用于设置编译工具的前缀

可以通过如下命令在qemu直接调用musl工具链：
scons --exec-path=C:\xxx\arm-linux-musleabi_for_i686-w64-mingw32\bin --exec-prefix=arm-linux-musleabi-

* comment out GenCconfigFile

* 解决部分env变量提前预载之后重载变量的问题

* 1.407/437 uart2 pins change to pd5/pd6. 2.uart and spi drivers support dma

* [bsp/at32] remove #ifndef

* [STM32][SPI]优化APBx时钟配置代码

Signed-off-by: Njaffer <jaffer.work@foxmail.com>

1.顺序修改回V1,保证每次都是当前数据发送完才跳出

* 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>

默认为project.xx 与原来保持一致
相关：https://club.rt-thread.org/ask/article/f998b21633f90916.html