[quant][refactor] Move some util functions from torch/quantization/fx/utils.py to torch/quantization/utils.py (#48107)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/48107
Test Plan: Imported from OSS
Reviewed By: supriyar
Differential Revision: D25026495
fbshipit-source-id: 3634b6b95a18670232600874b1e593180ea9f44c
