LayerNorm use Fused Multiply and Add (#40012)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/40012
Use Fused Multiply and Add
Test Plan: Tested using the test_layernorm_nnpi_fp16.py test case.
Reviewed By: hyuen
Differential Revision: D22039340
fbshipit-source-id: d979daac152f885318ddcbbb9d7108219d4743e9
