Fix risc-v s-mode issue.

[update] Fix STM32 USB driver matching hal library version

[kernel] define RT_USING_BIG_ENDIAN for the long-term version

[stm32l475] port for LVGL

[stm32][bsp] The sconscript script in the application folder increase…

[bsp][stm32][l475] add lcd_fill_array()

[stm32][l745] add lvgl demo

bsp/nuclei: update nuclei target support code

[bsp/essemi]update old bsp，add bsp es32f365x

[libc][posix] create 'posix' folder and move related files into it

[stm32][bsp] The sconscript script in the application folder increases the recursion searching capability

[update] add v4.0.4 changelog

we no longer use hbird_eval to stand for board using by
nuclei fpga development boards, we are now using nuclei_fpga_eval
to stand for it.

nowadays the fpga bitstream cpu freq is 16MHz, and uart tx/rx
both works at 115200bps, so we change the baudrate to 115200bps
Signed-off-by: Huaqi Fang <578567190@qq.com>

[update] RT-Thread Robot automatic submission

Merge pull request !307 from hongsenlin/ulog_backends

[update] RT-Thread Robot automatic submission

previous rt_hw_context_switch might cause the
task switch handling error.

See
https://github.com/Nuclei-Software/nuclei-sdk/commit/1a1a209e9363840d372c04b84ce733ea6b6e79f2#diff-ba922e02206af6c52163f0c34a7e76e427b7ea22f791329b62f2069241c57778Signed-off-by: Huaqi Fang <578567190@qq.com>

[update] bsp .config file and rtconfig.h file.

Merge pull request !350 from 傅尔先森/gitee_master