Removed the redundant SiLUActivation class.

[hisushanta]

Removed the redundant SiLUActivation class and now use nn.SiLU directly.

See now what looks like:

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[amyeroberts]

Thanks for adding this!

Could you run the slow model tests for IDEFICs, Mistral, Llama and EfficientNet to make sure that this is backwards compatible?

[hisushanta]

Hi! I first set RUN_SLOW=1 and then ran the PyTest command to verify that all of my tests passed successfully.

[HuggingFaceDocBuilderDev]

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