[Finsh] fix device_open issue when set_device in finsh.

components/finsh/finsh.h

@@ -411,7 +411,6 @@ struct finsh_parser
  *
  * The basic data type in finsh shell
  */
-
 enum finsh_type {
 	finsh_type_unknown = 0, /**< unknown data type */
 	finsh_type_void,		/**< void  			*/

components/finsh/shell.c

@@ -112,7 +112,7 @@ 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_EOK)
+    if (rt_device_open(dev, RT_DEVICE_OFLAG_RDWR | RT_DEVICE_FLAG_INT_RX) == RT_EOK)
     {
         if (shell->device != RT_NULL)
         {