control of observer/fake-quant operations (#26520)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/26520
Hooks to enable control of observer and fake quant that can be used by model.apply() to control fake quant during QAT
ghstack-source-id: 90897063
Test Plan: buck test caffe2/test:quantization -- --print-passing-details
Differential Revision: D17491155
fbshipit-source-id: 80ff0d7a1ac35c96e054b4f0165a73c56c2f53cc
