update moe_smooth_quant dispatch and v2 supports block_m is a multiple of 16

[junhaha666]

…

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Pull request overview

This PR updates the MoE smooth-per-token scaled quantization dispatch to better support block_m values that are multiples of 16, and adjusts the Python-side routing logic for small-token MoE stage1 cases.

Changes:

• Update moe_smooth_per_token_scaled_quant_v2 dispatch math to use a fixed block_split=16 and enforce block_m % 16 == 0.
• Add an is_balanced flag to moe_smooth_per_token_scaled_quant to control whether stage1 uses the v1 kernel or a smooth_per_token_scaled_quant fallback for small M.
• Remove outdated commented call examples in fused_moe_bf16_asm.py.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
csrc/kernels/quant_kernels.cu	Enforces block_m divisibility by 16 and changes v2 block splitting/indexing to be consistent for non-power-of-2 block_m (as long as divisible by 16).
aiter/ops/quant.py	Adds is_balanced flag and changes stage1 small-M dispatch behavior (v1 vs smooth-quant fallback).
aiter/fused_moe_bf16_asm.py	Removes commented-out alternative quant call paths around asm_moe.

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