Set FSDP `transformer_layer_cls_to_wrap` to `model._no_split_modules` ?
### Feature request

Currently, when training with FSDP, the Trainer expects to receive an `fsdp_config` argument specifying `fsdp_transformer_layer_cls_to_wrap`.

https://github.com/huggingface/transformers/blob/66954ea25e342fd451c26ec1c295da0b8692086b/src/transformers/trainer.py#L1394-L1406

I am wondering if we can set this automatically, when the model has a `_no_split_modules` attribute, e.g.

https://github.com/huggingface/transformers/blob/66954ea25e342fd451c26ec1c295da0b8692086b/src/transformers/models/opt/modeling_opt.py#L401

### Motivation

It would be a convenient feature to set this automatically. This argument is model-specific, but it might be nice to define training arguments independently of a specific model type.

### Your contribution

Happy to help make a PR. Would be great if you can confirm whether this would be desirable or if I am misunderstanding something. Thanks!
cc @pacman100 <|||||>Any thoughts about this? Maybe also cc @stas00?<|||||>Unfortunately I don't have experience with FSDP to contribute to this discussion.<|||||>@pacman100 Friendly ping<|||||>Hello @apoorvkh, the code part you highlighted is enabled now only when using FSDP+XLA. For general FSDP, internally everything is handled by Accelerate. It happens here: https://github.com/huggingface/transformers/blob/66954ea25e342fd451c26ec1c295da0b8692086b/src/transformers/training_args.py#L1533-L1556

`fsdp_transformer_layer_cls_to_wrap` support specifying multiple modules but most of the time it is enough to specify the `_no_split_modules`. So, we can have `_no_split_modules` as a default in case the user doesn't specify it when passing `--fsdp full_shard auto_wrap`. 
<|||||>PRs https://github.com/huggingface/accelerate/pull/1753 and https://github.com/huggingface/transformers/pull/24980 should add this capability wherein it will try `model. _no_split_modules ` if `fsdp_transformer_layer_cls_to_wrap ` isn't specified. Can you try it out?<|||||>Very cool, thanks a ton! I will try it out and let you know.<|||||>Just circling back, works on my end -- thanks again!