silu_and_mul: qwen2.5-vl VIT intermediate_size=3420, but vec_size in flashinfer is allways 16

[CrimsonDump]

reproduce by replace dim with 3420

flashinfer/tests/utils/test_activation.py

Line 40 in f84ac1c

@pytest.mark.parametrize("dim", [128, 256, 512, 2048, 4096, 11008, 16384])

Also you can refer to:
https://github.com/alibaba/rtp-llm/blob/main/3rdparty/flashinfer/0010-silu-mul-vec-size.patch