Revert D32318435: [quant][embdding qat] Add FX support for QAT EmbeddingBag
Test Plan: revert-hammer
Differential Revision:
D32318435 (https://github.com/pytorch/pytorch/commit/4484c045132631783a1b15664d7cf528a1905395)
Original commit changeset: 8b5d1a5d5422
fbshipit-source-id: e46d431f92a5c3f86c757695164d1eb5b0041298
