finsh: open the finsh device with RT_DEVICE_FLAG_STREAM

components/finsh/shell.c

@@ -113,7 +113,8 @@ void finsh_set_device(const char* device_name)
     /* check whether it's a same device */
     if (dev == shell->device) return;
     /* open this device and set the new device in finsh shell */
-    if (rt_device_open(dev, RT_DEVICE_OFLAG_RDWR | RT_DEVICE_FLAG_INT_RX) == RT_EOK)
+    if (rt_device_open(dev, RT_DEVICE_OFLAG_RDWR | RT_DEVICE_FLAG_INT_RX |\
+                       RT_DEVICE_FLAG_STREAM) == RT_EOK)
     {
         if (shell->device != RT_NULL)
         {