Fix device error while calculating loss in Trainer

[echo-yi]

What does this PR do?

Fixes ValueError in Trainer when tr_loss and tr_loss_step are on different devices. This error happens when I use device_map='auto' and ORPOTrainer together.

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Who can review?

@amyeroberts

[amyeroberts]

Hi @echo-yi, thanks for opening this PR!

Based on the warning message in the diff - it seems this is flagging device placement which should be handled elsewhere. cc @muellerzr who might know more

[SunMarc]

Hey @echo-yi, I've opened up a PR to fix the issue you are facing. The fix should live in TRL instead. LMK if this solves your issue !