convert double to single float

tests/fpgadataflow/test_convert_to_hls_layers_synthetic.py

@@ -149,7 +149,7 @@ def make_model(ch, ifmdim):
 def test_convert_to_hls_layers_synthetic(ch, ifmdim, idt):
     model = make_model(ch, ifmdim)
     model.save(export_onnx_path)
-    model = ModelWrapper(export_onnx_path)
+    model = ModelWrapper(export_onnx_path, fix_float64=True)
     model = model.transform(InferShapes())
     model = model.transform(FoldConstants())
     model = model.transform(GiveUniqueNodeNames())