Work around cuFFT skews
Work around cuFFT skews

It almost seems like cuFFT misbehaves specifically when I use the "right"
width for the field. This fixes it at the cost of one column getting
shifted by a pixel. Enough to continue testing, but no serious long-
term solution.

SKA-ScienceDataProcessor/RC,SKA-ScienceDataProcessor/RC,SKA-ScienceDataProcessor/RC,SKA-ScienceDataProcessor/RC,SKA-ScienceDataProcessor/RC