Remove unnecessary preprocessing steps of VI-LayoutXLM to improve performance.

[Bourn3z]

Thank you for your contribution to the MindOCR repo. Before submitting this PR, please make sure:

• [ ] You have read the Contributing Guidelines on pull requests
• [ ] Your code builds clean without any errors or warnings
• [ ] You are using approved terminology
• [ ] You have added unit tests

Motivation

删除VI-LayoutXLM中不必要的图片预处理步骤，提升模型性能。 Remove unnecessary preprocessing steps of VI-LayoutXLM to improve performance.

Test Plan

(How should this PR be tested? Do you require special setup to run the test or repro the fixed bug?)

Related Issues and PRs

(Is this PR part of a group of changes? Link the other relevant PRs and Issues here. Use https://help.github.com/en/articles/closing-issues-using-keywords for help on GitHub syntax)