[xpu]support moe models on XPU platform

[yma11]

Essential Elements of an Effective PR Description Checklist

• The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
• The test plan, such as providing test command.
• The test results, such as pasting the results comparison before and after, or e2e results
• (Optional) The necessary documentation update, such as updating supported_models.md and examples for a new model.

Purpose

Support models like ehristoforu/Falcon3-MoE-2x7B-Insruct, mistralai/Mixtral-8x7B-Instruct-v0.1 on XPU platform. For complicated models which require more moe releated kernels, will upstream support later as dependencies not published.

Test Plan

VLLM_ALLOW_LONG_MAX_MODEL_LEN=1 VLLM_WORKER_MULTIPROC_METHOD=spawn python3 examples/offline_inference/basic/generate.py --model ehristoforu/Falcon3-MoE-2x7B-Insruct --enforce-eager --dtype=float16 --trust_remote_code

Test Result

(Optional) Documentation Update

[gemini-code-assist]

Code Review

This pull request introduces support for Falcon3-MoE models on the XPU platform by adding XPU-specific logic to the FusedMoE layer. The changes leverage intel-extension-for-pytorch for the MoE implementation on XPU.

I've identified a couple of issues that should be addressed to ensure correctness and maintainability:

1. A configuration parameter is hardcoded, which should be made configurable for consistency and performance tuning.
2. The new forward_xpu method has an incomplete implementation that silently ignores crucial parameters. This is a critical issue that could lead to incorrect model behavior for other MoE models.

[github-actions]

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[jikunshang]

can you rename the PR title? I think this change is not for falcon only. xpu should not support any MoE model before?

[yma11]

can you rename the PR title? I think this change is not for falcon only. xpu should not support any MoE model before?

updated. W/o this change, no MoE models can be supported but for models like deepseek, we need more kernels that are available in ipex 2.8.

[xuechendi]

@yma11 , with this PR, we will continue the optimizations on ipex.llm.modules.GatedMLPMOE right?
If this PR is ready, @jikunshang , please approve

[DarkLight1337]

Can you merge from main to fix the CI failures?