[qunat][fx][bc-breaking] Remove "additional_qat_mapping" key from prepare_custom_config_dict (#75387)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/75387
This is now replaced with backend_config_dict, we don't want to expose the implementation detail to
users. We'll have docs for backend_config_dict later
Test Plan:
python test/test_quantization.py TestQuantizeFx
python test/test_quantization.py TestQuantizeFxOps
Imported from OSS
Reviewed By: vkuzo
Differential Revision: D35451955
fbshipit-source-id: 77ede61f1d8f169dc1e1e6d847244ba99a97ab76
(cherry picked from commit 953576259fdc8827437acb6f5d04e584e37a7d64)