remove cfg in _load_model_state in nlp_models
We patched cfg issue in modelPT level in https://github.com/NVIDIA/NeMo/pull/3170.
Revert the cfg arg in `_load_model_state` in nlp_models in https://github.com/NVIDIA/NeMo/pull/3149 since it will break the fix and is deprecated in PTL. 

Signed-off-by: fayejf <fayejf07@gmail.com>