[NNPI] Support fp32 bias in NNPI Backend (#38596)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/38596
ATT.
Test Plan:
unittests in the diff
```
buck test mode/dev //glow/fb/test/numerics:test_fc_nnpi_int8nnpi -- 'test_int8_fc_simple_fp32_bias \(glow\.fb\.test\.numerics\.test_fc_nnpi_int8\.Int8FCTest\)'
```
Reviewed By: jackm321
Differential Revision: D20474831
fbshipit-source-id: 9c49a71eb1926466013a196a3d6e60cdb25cf721
