add_observer: respect device affinity for ReLU (#39337)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/39337
In #39031 we made fake quantize respect device affinity of the
original module. However, that PR only handled modules with parameters
or buffers, and did not work properly for `ReLU`.
Fixing the logic to also work for `ReLU` by passing the parent's
device when adding observers.
Test Plan:
```
python test/test_quantization.py TestDistributed.test_device_affinity
```
Imported from OSS
Differential Revision: D21821243
fbshipit-source-id: cc6abda3694b80ce8ba0440dc6c1b5b58f3c0066
