missing update running_task

This commit fixes the regression from https://github.com/apache/nuttx/pull/14865

Signed-off-by: hujun5 <hujun5@xiaomi.com>

arch/xtensa/src/common/xtensa_assert.c

@@ -65,6 +65,13 @@
 
 void xtensa_panic(int xptcode, uint32_t *regs)
 {
+  struct tcb_s **running_task = &g_running_tasks[this_cpu()];
+
+  if (*running_task != NULL)
+    {
+      (*running_task)->xcp.regs = regs;
+    }
+
   up_set_interrupt_context(true);
 
   /* We get here when a un-dispatch-able, irrecoverable exception occurs */