What does this PR do?

In #34198, the line loss *= self.args.gradient_accumulation_steps was introduced due to Negate accelerate grad accum div. This change was made to correct errors encountered during gradient accumulation. However, the scaling should only occur when compute_loss_func is used, so the code was modified accordingly.

Before submitting

• [ ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• [x] Did you read the contributor guideline, Pull Request section?
• [ ] Was this discussed/approved via a Github issue or the forum? Please add a link to it if that's the case.
• [ ] Did you make sure to update the documentation with your changes? Here are the documentation guidelines, and here are tips on formatting docstrings.
• [ ] Did you write any new necessary tests?

Who can review?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag members/contributors who may be interested in your PR. @muellerzr @ArthurZucker