[SR] Fuse quantized linear/relu (#75775)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/75775
fbgemm kernels already implement the fused kernel, no reason not to use it
ghstack-source-id: 155450342
Test Plan: New unit tests
Reviewed By: navahgar
Differential Revision: D35633297
fbshipit-source-id: a744a33a65ce7dbb9ce8900dbe091b6d56dd4e48
(cherry picked from commit b1361b349862715aa17e6318c5e658cd6401a464)
