[qunat][graphmode][fx] Standalone module takes float as input and output (#48671)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/48671
Standalone module might be called separately so it's better to use float
as interface.
Test Plan: Imported from OSS
Reviewed By: vkuzo
Differential Revision: D25256184
fbshipit-source-id: e209492a180ce1f81f31c8d6057956a74bad20b1
