Automated submodule update: FBGEMM (pytorch#74423)

Summary:
This is an automated pull request to update the first-party submodule for [pytorch/FBGEMM](https://github.com/pytorch/FBGEMM).

New submodule commit: pytorch/FBGEMM@43c0f12

Pull Request resolved: pytorch#74423

Test Plan: Ensure that CI jobs succeed on GitHub before landing.

Reviewed By: jspark1105

Differential Revision: D34993535

fbshipit-source-id: c40e2100810b40b58a2b3f536e5b132fc4b8acae
(cherry picked from commit 65e1782)