Add description of make command

deploy/lite/readme.md

@@ -238,7 +238,7 @@ use_direction_classify 0 # 是否使用方向分类器，0表示不使用，1
  上述步骤完成后就可以使用adb将文件push到手机上运行，步骤如下：
 
  ```
- # 执行编译，得到可执行文件ocr_db_crnn
+ # 执行编译，得到可执行文件ocr_db_crnn, 第一次执行此命令会下载opencv等依赖库，下载完成后，需要再执行一次
  make -j
 
  # 将编译的可执行文件移动到debug文件夹中

deploy/lite/readme_en.md

@@ -238,6 +238,7 @@ After the above steps are completed, you can use adb to push the file to the pho
 
  ```
  # Execute the compilation and get the executable file ocr_db_crnn
+ # The first execution of this command will download dependent libraries such as opencv. After the download is complete, you need to execute it again
  make -j
  # Move the compiled executable file to the debug folder
  mv ocr_db_crnn ./debug/