[Core] pass revision in the loading_kwargs.

[sayakpaul]

What does this PR do?

No idea why we didn't pass revision.

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[yiyixuxu]

I don't think we need to pass down this argument since:

1. load_sub_model is only used inside DiffusionPipeline.from_pretrained()
2. we used the revision argument to download the correct checkpoints here, once we have the cached folder we don't need this argument anymore

   diffusers/src/diffusers/pipelines/pipeline_utils.py

   Line 1088 in c09bb58

   cached_folder = cls.download(

but I'm ok with this PR - I just don't think it makes any difference

[sayakpaul]

You're absolutely right! WDYT about removing revision from load_sub_model() then? I think we should eliminate the confusion (it's not used in the method).

[DN6]

Yes, I think we can remove it from load_sub_model if it's not used.

[yiyixuxu]

yep on the same page - we can remove it

[sayakpaul]

@yiyixuxu requesting for another review.

[yiyixuxu]

thanks!