risc-v/riscv_assert.c Fix dumping of status from ISR

The status dump did not work if the first fault triggers before
the first context switch (during nx_start()).

arch/risc-v/src/common/riscv_assert.c

@@ -332,8 +332,7 @@ static void riscv_dumpstate(void)
 
   if (CURRENT_REGS)
     {
-      memcpy(rtcb->xcp.regs,
+      rtcb->xcp.regs = (uintptr_t *)CURRENT_REGS;
-             (uintptr_t *)CURRENT_REGS, XCPTCONTEXT_SIZE);
     }
   else
     {