[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 <578567190@qq.com>

libcpu/risc-v/nuclei/cpuport.c

@@ -143,9 +143,7 @@ void rt_hw_context_switch_interrupt(rt_ubase_t from, rt_ubase_t to)
  */
 void rt_hw_context_switch(rt_ubase_t from, rt_ubase_t to)
 {
-    rt_interrupt_from_thread = from;
-    rt_interrupt_to_thread = to;
-    RT_YIELD();
+    rt_hw_context_switch_interrupt(from, to);
 }
 
 /**