modify code style

src/io/paddle_mobile.h

@@ -48,9 +48,9 @@ class PaddleMobile {
   bool Load(const std::string &model_path, const std::string &para_path,
             bool optimize = false, bool quantification = false,
             int batch_size = 1);
-    /*
-     * @b 设置线程数, 当 cmake 中开启 openmp 时生效
-     * */
+  /*
+   * @b 设置线程数, 当 cmake 中开启 openmp 时生效
+   * */
   void SetThreadNum(int num);
 
   /*