support amp training for video classification models (#5023)
support amp training for video classification models (#5023)

* support amp training for video classification models

* Removed extra empty line and used scaler instead of args.amp as function argument

* apply formating to pass lint tests

Co-authored-by: Konstantinos Bozas <87183527efae2689bc19137d29538704f63c0006@kbz-mbp.broadband>
pytorch/vision,pytorch/vision,pytorch/vision,pytorch/vision,pytorch/vision,pytorch/vision