samples: gpu: super_resolution: disable simple optical flow
samples: gpu: super_resolution: disable simple optical flow

The cv::superres::createOptFlow_Simple() function along with the
simple optical flow class implementation is currently commented out
in the superres module's code, so comment it out in the example as well.

opencv/opencv,opencv/opencv,opencv/opencv,apavlenko/opencv,apavlenko/opencv,opencv/opencv,opencv/opencv,apavlenko/opencv,apavlenko/opencv,opencv/opencv,opencv/opencv,apavlenko/opencv,opencv/opencv,opencv/opencv,apavlenko/opencv,opencv/opencv