fix bug during HPU inference (#2280)

Signed-off-by: xinhe3 <[email protected]>
Co-authored-by: xinhe3 <[email protected]>

Author: xin3he

neural_compressor/evaluation/lm_eval/models/huggingface.py

@@ -359,7 +359,7 @@ def config(self):
     @property
     def model(self):
         # returns the model, unwrapping it if using Accelerate
-        if hasattr(self, "accelerator"):
+        if hasattr(self, "accelerator") and self._model is not None:
             return self.accelerator.unwrap_model(self._model)
         else:
             return self._model