MLBEDSW-4960: convert_resizebilinear_1x1_to_add creates constant output tensor

Sets second input tensor of resize op to be constant and refactored function.

Signed-off-by: wilisa01 <william.isaksson@arm.com>
Change-Id: I496764f18b4c1ae0fa1a828dd7a90e937a42d41b
diff --git a/ethosu/vela/tflite_graph_optimiser.py b/ethosu/vela/tflite_graph_optimiser.py
index 73137fe..af8695b 100644
--- a/ethosu/vela/tflite_graph_optimiser.py
+++ b/ethosu/vela/tflite_graph_optimiser.py
@@ -289,18 +289,14 @@
     op.type = Op.Add  # original_type will stay as Op.ResizeBilinear or Op.ResizeNearestNeighbor
     op.name = op.name + "_add"
     # Create an input tensor filled with zeros
+    name = op.inputs[1].name + "_add"
+    dtype = op.inputs[0].dtype
     shape = op.ofm_shapes[0].as_list()
-    tens = Tensor(shape, op.inputs[0].dtype, op.inputs[1].name + "_add")
-    tens.values = np.zeros(shape, tens.dtype.as_numpy_type())
-    tens.quantization = QuantizationParameters(0.0, 255.0)
-    tens.quantization.scale_f32 = 1.0
-    tens.quantization.zero_point = 0
-    tens.consumer_list = [op]
-    tens_op = op.inputs[1].ops[0]
-    tens_op.set_output_tensor(tens)
-    # Set the add inputs
-    op.inputs[1] = op.inputs[0]
-    op.inputs[0] = tens
+    values = np.zeros(shape, dtype.as_numpy_type())
+    quantization = QuantizationParameters(0.0, 255.0)
+    quantization.scale_f32 = 1.0
+    quantization.zero_point = 0
+    op.set_input_tensor(create_const_tensor(name, shape, dtype, values, quantization=quantization), 1)
     op.set_ifm_ofm_shapes()
     DebugDatabase.add_optimised(op, op)