[quant][graphmode][refactor] Factor out getFixedQParamOpFusionInfo (#38359)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/38359
Test Plan: Imported from OSS
Differential Revision: D21559807
fbshipit-source-id: 13a67049a189ca43dcdae4b42bab0847821b3cd5
