[quant] Fix histogram observer to work with QAT on GPU (#34232)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/34232
By default `torch.zeros` creates the tensor on GPU. Need to specify the device argument to get it to work correctly on GPU during QAT.
Test Plan:
1. Tested by running QAT on GPU
2. python test/test_quantization.py
Imported from OSS
Differential Revision: D20286351
fbshipit-source-id: 745723c85d902870c56c1c7492f26cb027ae9dc6
