fix _setup_devices in case where there is no torch.distributed package in build
# What does this PR do?

At least in some instances (e.g. conda on my m1), torch is built without distributed support enabled. This takes the form of torch.distributed.is_available() returning false and torch.distributed.is_initialized() raising an exception. In this particular method, it's enough to skip the check if it's not available.

This behavior causing this crash was added in https://github.com/huggingface/transformers/pull/16487

## 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](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md#start-contributing-pull-requests),
      Pull Request section?
- [ ] Was this discussed/approved via a Github issue or the [forum](https://discuss.huggingface.co/)? 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](https://github.com/huggingface/transformers/tree/main/docs), and
      [here are tips on formatting docstrings](https://github.com/huggingface/transformers/tree/main/docs#writing-source-documentation).
- [ ] Did you write any new necessary tests?

  I could mock this out but it seems painful and unnecessary. I can try to do it if you want.


## Who can review?

Seems like @sgugger is the best reviewer here?
_The documentation is not available anymore as the PR was closed or merged._<|||||>done!<|||||>Thanks!