TP4 FP4 for MI355X SGLang

[cquil11]

Fix issues in https://github.com/InferenceMAX/InferenceMAX/pull/247
Test
Have inference engineer verify performance

[chunfangamd]

DSR1 FP4 + TP4 Issue

• rocm/7.0:rocm7.0_ubuntu_22.04_sgl-dev-v0.5.2-rocm7.0-mi35x-20250915: Work
• lmsysorg/sglang:v0.5.5.post2-rocm700-mi35x: Failed

Problem identified: The Aiter kernel probably needs a fix, from the latest optimisation pick-up

Xiao, Hai is working on this

[HaiShaw]

The DSr1 FP4 + TP4 is fixed in lmsysorg/sglang:v0.5.6.post1-rocm700-mi35x.
Please add --attention-backend aiter explicitly.
Also please enable FP8 KV cache with --kv-cache-dtype fp8_e4m3.
Need to tune other running configures, e.g. --max-running-requests