Automated submodule update: FBGEMM (#90489)
This is an automated pull request to update the first-party submodule for [pytorch/FBGEMM](https://github.com/pytorch/FBGEMM).
New submodule commit: https://github.com/pytorch/FBGEMM/commit/81ba6c51ecece07190601a09e8d88a04d0581dbc
Test Plan: Ensure that CI jobs succeed on GitHub before landing.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/90489
Approved by: https://github.com/malfet
