pin_memory -> dataloader_pin_memory
Ref: https://github.com/huggingface/transformers/pull/9857#issuecomment-769256215

This PR adds a new argument `dataloader_pin_memory` to `TrainingArguments`. You can use this to pin memory in `DataLoader`.
Updated with review comments. Please let me know if/when it's okay to merge :) <|||||>Good for me, thanks a lot!<|||||>this is much better, thank you for the adjustment, @abhishekkrthakur 