完成rtthread适配

cpu/timer.c

@@ -75,7 +75,7 @@ static void run(riscv_t *riscv, const struct device_t* device) {
 
 static void *timer_thread(void *arg) {
   while (1) {
-    milliseconds_sleep(1000);
+    milliseconds_sleep(1);
     pthread_mutex_lock(&g_self.lock);
     g_self.ins_count++;
     pthread_mutex_unlock(&g_self.lock);