[Relax][Frontend][ONNX]fix onnx frontend parse (#16395)

fix onnx frontend

Co-authored-by: cheng wen <chengven027-intellif>

Author: chengven027

python/tvm/relax/frontend/onnx/onnx_frontend.py

@@ -1983,8 +1983,8 @@ def from_onnx(self, graph: onnx.onnx_ml_pb2.ModelProto, opset: int) -> IRModule:
         with self.bb.function("main"):
             with self.bb.dataflow() as df:  # pylint: disable=invalid-name, unused-variable
                 self.opset = opset
-                self._parse_graph_input(graph)
                 self._parse_graph_initializers(graph)
+                self._parse_graph_input(graph)
                 self._check_for_unsupported_ops(graph)
                 self._construct_nodes(graph)