[run_clm example] add torch_dtype option for model load.
for BLOOM 175B model. peak memory will reduce about 350G for inference. the weight of BLOOM in model hub is bfloat16

Signed-off-by: Wang, Yi A <yi.a.wang@intel.com>

# What does this PR do?

reduce the peak memory for BLOOM inference.

## Before submitting
- [ ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
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      Pull Request section?
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      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?


## Who can review?

- trainer: @sgugger

@yao-matrix @jiqing-feng @sgugger please help to review<|||||>_The documentation is not available anymore as the PR was closed or merged._<|||||>@sgugger done,  add other torch dtypes per review comment