MLBEDSW-7754: Performance estimator is not using write/read shapes

- npu_performance now uses write/read shapes instead of using ifm/ofms
for memory cycle estimations.

- also fixes a would be bug in the tflite_graph_optimiser, where one
read shape is not Shape4D.

Change-Id: I2067069a713d2cf9e65a5cc227e803de79940fff
Signed-off-by: William Isaksson <william.isaksson@arm.com>