[libcpu][nuclei] Fix context switch  in nuclei
[libcpu][nuclei] Fix context switch  in nuclei

previous rt_hw_context_switch might cause the
task switch handling error.

See
https://github.com/Nuclei-Software/nuclei-sdk/commit/1a1a209e9363840d372c04b84ce733ea6b6e79f2#diff-ba922e02206af6c52163f0c34a7e76e427b7ea22f791329b62f2069241c57778

Signed-off-by: Huaqi Fang <340cc3cd9ffd795ec7885734e62ff7093943c58b@qq.com>

nongxiaoming/rt-thread,hezlog/rt-thread,hezlog/rt-thread,nongxiaoming/rt-thread,RT-Thread/rt-thread,hezlog/rt-thread,geniusgogo/rt-thread,RT-Thread/rt-thread,RT-Thread/rt-thread,hezlog/rt-thread,geniusgogo/rt-thread,nongxiaoming/rt-thread,nongxiaoming/rt-thread,RT-Thread/rt-thread,geniusgogo/rt-thread,RT-Thread/rt-thread,geniusgogo/rt-thread,hezlog/rt-thread,nongxiaoming/rt-thread,geniusgogo/rt-thread,hezlog/rt-thread,RT-Thread/rt-thread,geniusgogo/rt-thread,nongxiaoming/rt-thread,geniusgogo/rt-thread,RT-Thread/rt-thread,nongxiaoming/rt-thread,hezlog/rt-thread