修复低概率终端无法输入问题 (#6464)

* [ulog] Fix the problem that the terminal cannot input

* [mem] Fix NULL pointer access

components/utilities/ulog/backend/console_be.c

@@ -31,11 +31,7 @@ void ulog_console_backend_output(struct ulog_backend *backend, rt_uint32_t level
     }
     else
     {
-        rt_uint16_t old_flag = dev->open_flag;
-
-        dev->open_flag |= RT_DEVICE_FLAG_STREAM;
         rt_device_write(dev, 0, log, len);
-        dev->open_flag = old_flag;
     }
 #else
     rt_hw_console_output(log);