[vLLM][moe] Enable DeepGEMM SiLU FP8 moe fallback and update skiplist

[sarah12121212]

This updates the vLLM patch to let the DeepGEMM SiLU FP8 MoE test run on XPU.

The patch:

• avoids querying CUDA device capability unless the current platform is CUDA
• lets XPU use the existing Triton fallback path (logic now only enters the DeepGEMM fast path when the platform is CUDA and the CUDA arch is supported)
• applies the same FP8-boundary tolerance handling on XPU that ROCm already uses
• unskips test_silu_mul_fp8_quant_deep_gemm in the default and Xe2 MoE skiplists

CI Validation:

PVC:
BMG: