OS: Fix rt-thread task switch when swi triggered by other harts

MCAUSE : 0x18000001
MDCAUSE: 0x1
MEPC   : 0xdeadbeee
MTVAL  : 0xdeadbee8
HARTID : 3
ra: 0x0, tp: 0xfea007a0, t0: 0xdeadbeef, t1: 0xdeadbeef, t2: 0xdeadbeef, t3: 0xdeadbeef, t4: 0xdeadbeef, t5: 0xdeadbeef, t6: 0xdeadbeef
a0: 0xdeadbeef, a1: 0xdeadbeef, a2: 0xdeadbeef, a3: 0xdeadbeef, a4: 0xdeadbeef, a5: 0xdeadbeef, a6: 0xdeadbeef, a7: 0xdeadbeef
cause: 0x18000001, epc: 0xdeadbeee
msubm: 0x80

Signed-off-by: Huaqi Fang <578567190@qq.com>

OS/RTThread/libcpu/risc-v/nuclei/cpuport.c

@@ -141,6 +141,11 @@ void xPortTaskSwitch(void)
     /* Clear Software IRQ, A MUST */
     SysTimer_ClearSWIRQ();
     rt_thread_switch_interrupt_flag = 0;
+    // make from thread to be to thread
+    // If there is another swi interrupt triggered by other harts
+    // not through rt_hw_context_switch or rt_hw_context_switch_interrupt
+    // the task switch should just do a same task save and restore
+    rt_interrupt_from_thread = rt_interrupt_to_thread;
 }
 
 void vPortSetupTimerInterrupt(void)