Use microsecond timer for heap use as the timer is in microsecond mode

esp-link/main.c

@@ -143,7 +143,7 @@ void user_init(void) {
 #ifdef SHOW_HEAP_USE
   os_timer_disarm(&prHeapTimer);
   os_timer_setfn(&prHeapTimer, prHeapTimerCb, NULL);
-  os_timer_arm(&prHeapTimer, 10000, 1);
+  os_timer_arm_us(&prHeapTimer, 10 * 1000000, 1);
 #endif
 
   struct rst_info *rst_info = system_get_rst_info();