* [rtduino][lpc55s69] 纠正uart引脚错误并使能相关依赖项
Co-authored-by: Man, Jianting (Meco) <920369182@qq.com>

* add support usb driver

* fixed code format error

[rt-smart] handling kernel from accessing unmapped user stack

1.修正RTduino框架下的引脚错误
2.Kconfig新增RTduino依赖项
3.README文档完善
4.上传LPC55s69兼容arduino部分引脚图

fix bugs on cache maintenance when starting user app

添加一个status，判断I2C执行结果来修复i2c传输始终正确的BUG。

* add cputimer frame

* add cputime sleep

* ctime use cputime

* Processing cputime has no timeout function

* Migration cputime Code

* formatting file

* 整理代码

* add document copyright information

* 改 cputime_timer 为 cputimer

* 简化 _cputimer_list 初始化

* rt_cputimer_create -> rt_cputimer_init

* Remove RT_USING_CPUTIME and code cleanup.

* Remove RT_USING_CPUTIME in cputimer.c
* Set set_next_timeout as static function.

---------
Co-authored-by: NBernard Xiong <bernard.xiong@gmail.com>

* [rt-smart/mem] remove pv_offset

* [rt-smart] list kernel space command

* [rt-smart] restore ioremap region

* [revert] restore kernel space isolation

* [rt-smart/pv_off] code format

* [rt-smart] add get_pvoff()

* [pvoffset] pvoff as constant for C codes

* [pvoff] pvoff as interfaces

* [FDT] Fix POSIX compatibility for string.h

* [FDT] format libfdt code.

* [FDT] format libfdt code.