fix split node conversion (#1124)

Author: mengniwang95

neural_compressor/adaptor/ox_utils/operators/split.py

@@ -51,7 +51,7 @@ def convert(self):
         quantized_input_names = []
         quantized_input_names.append(parent.input[0])
         if len(node.input) > 1:
-            quantized_input_names = quantized_input_names.extend(node.input[1:])
+            quantized_input_names.extend(node.input[1:])
         outputs = []
         for output in node.output:
             if output in self.quantizer.model.input_name_to_nodes: