[rocm] scaled_grouped_mm support gfx942 fp8 data type

[xiaobochen-amd]

This PR adds rowwise support for scaled_grouped_mm on gfx942 with float8 dtypes. PyTorch already provides float8 support on gfx942, and this change aligns torchao with the existing PyTorch capability. Relevant unit tests have been added and all tests pass.

docker:  rocm/primus:v25.10

torch==2.11.0.dev20251221+rocm7.1

pytest test/prototype/moe_training/test_scaled_grouped_mm.py

[pytorch-bot]

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