[quant][graphmode][fx] Support quantizing FloatFunctional (#46634)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/46634
Test Plan: Imported from OSS
Reviewed By: vkuzo
Differential Revision: D24438227
fbshipit-source-id: f33439d51112e13f59ee4292e804495d38fa3899
