[Feat] support quantization for GLM-IMAGE (#2292)

Signed-off-by: Lancer <maruixiang6688@gmail.com>
Signed-off-by: Hongsheng Liu <liuhongsheng4@huawei.com>
Co-authored-by: Hongsheng Liu <liuhongsheng4@huawei.com>

vllm_omni/diffusion/data.py

@@ -759,7 +759,7 @@ class OmniDiffusionConfig:
 
         # Backwards-compatibility: map "quantization" to "quantization_config"
         # so callers using the old field name still work.
-        if "quantization" in kwargs and "quantization_config" not in kwargs:
+        if "quantization" in kwargs and kwargs.get("quantization_config") is None:
             kwargs["quantization_config"] = kwargs.pop("quantization")
         else:
             kwargs.pop("quantization", None)