Use head_dim if in config for RoPE
Author: suiyoubi
Pull request: yes

# What does this PR do?

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Fixes issue that when head_dim * num_attention_heads != hidden_size, the RoPE is not initialized correctly


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Comments:
@gante could you please take a look at this PR ? 

Hi @ArthurZucker @gante , may I ask if there is any update on this ? 

The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/transformers/pr_32495). All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.