Deprecating `position_ids` in GPTJ
### System Info

latest transformers version, pytorch

### Who can help?

Hi @ArthurZucker and @younesbelkada, let me know if someone else should be tagged in this, esp. considering this is a harmless "bug", not something really urgent.

Basically what the title says: I think the position_ids in the [GPT-J code](https://github.com/huggingface/transformers/blob/main/src/transformers/models/gptj/modeling_gptj.py) should be deprecated, since they are not used anywhere as far as I can tell. Something along the line of what bloom does at:
https://github.com/huggingface/transformers/blob/main/src/transformers/models/bloom/modeling_bloom.py#L891

I can also submit a PR if you want, just wanted to make sure I didn't overlook anything.

Let me know,
Clément

### Information

- [ ] The official example scripts
- [ ] My own modified scripts

### Tasks

- [ ] An officially supported task in the `examples` folder (such as GLUE/SQuAD, ...)
- [ ] My own task or dataset (give details below)

### Reproduction

N/A

### Expected behavior

Cleaner code, no useless no-op
This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

Please note that issues that do not follow the [contributing guidelines](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md) are likely to be ignored.<|||||>Friendly ping @ArthurZucker and @younesbelkada <|||||>I agree with you, opened a PR for this. Thanks for reporting. 