[Misc] move omni_diffusion.py to vllm_omni.entrypoints (#312)

Signed-off-by: zjy0516 <riverclouds.zhu@qq.com>

vllm_omni/entrypoints/omni.py

@@ -2,8 +2,8 @@
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 import os
 
-from vllm_omni.diffusion.omni_diffusion import OmniDiffusion
 from vllm_omni.diffusion.utils.hf_utils import is_diffusion_model
+from vllm_omni.entrypoints.omni_diffusion import OmniDiffusion
 from vllm_omni.entrypoints.omni_llm import OmniLLM