Add assertion when loading cpu and cuda kernel fails

quantization.py

@@ -443,7 +443,7 @@ def quantize(model, weight_bit_width, use_quantization_cache=False, empty_init=F
     except:
         if kernels is None:  # CUDA kernels failed
             print("Cannot load cpu or cuda kernel, quantization failed:")
-            assert kernels is None
+            assert kernels is not None
         print("Cannot load cpu kernel, don't use quantized model on cpu.")
 
     current_device = model.device