Add contributed HW support into README (#5240)
This PR add contributed HW support into README. This section provides
the following information:
1. Which HW is supported?
2. How is this HW validated? By contributor or with upstream workflow?
The purpose is to help DeepSpeed user understand whether their HW is
supported by DeepSpeed and how is their HW validated.
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Co-authored-by: Logan Adams <114770087+loadams@users.noreply.github.com>
