[quant][fx] Make scale, zero_point buffers in the model, use FQN (for quantize_per_tensor ops) (#51171)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/51171
Following up on previous PR, this PR makes scale and zero_point for quantize_per_tensor to be
registered as buffers in the module.
Currently the dtype is still stored as attr (not registered as buffer) since we can only register tensor types.
Test Plan:
python test/test_quantization.py test_qparams_buffers
Imported from OSS
Reviewed By: jerryzh168
Differential Revision: D26092964
fbshipit-source-id: a54d914db7863402f2b5a3ba2c8ce8b27c18b47b
