feat(//py/torch_tensorrt/dynamo): Support for BF16

[narendasan]

Description

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Fixes # (issue)

Type of change

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• Bug fix (non-breaking change which fixes an issue)
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[peri044]

LGTM

[HolyWu]

tensorrt module doesn't have bf16 attribute.

Python 3.10.12 (main, Nov 20 2023, 15:14:05) [GCC 11.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import tensorrt
>>> tensorrt.__version__
'10.0.1'
>>> hasattr(tensorrt, "bf16")
False
>>> hasattr(tensorrt, "bfloat16")
True