improving TimmBackbone to support FrozenBatchNorm2d (#27160)
* supporting freeze_batch_norm_2d
* supporting freeze_batch_norm_2d
* including unfreeze + separate into methods
* fix typo
* calling unfreeze
* lint
* Update src/transformers/models/timm_backbone/modeling_timm_backbone.py
Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>
---------
Co-authored-by: Rafael Padilla <rafael.padilla@huggingface.co>
Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>