Generalization for mac estimation for conv2d when groups is not 1

[poyupaulchen]

neuralSPOT/tools/ns_tflite_analyze.py

Line 189 in 26a212f

macs = (

if groups of conv2d is considered, macs should be like this for generalization

macs = (
                        filter["shape"][1]
                        * filter["shape"][2]
                        * filter["shape"][3] 
                        * outputs["shape"][1]
                        * outputs["shape"][2]
                        * outputs["shape"][3] 
                    )

The total # of MACs will be sizeof(filter) * sizeof(output)