DngOpcodes::DeltaRowOrCol: fix cropped ROI handling
DngOpcodes::DeltaRowOrCol: fix cropped ROI handling

Deltas/scales would be only present for the pixels in ROI,
yet we check (and access!) using non-ROI, but global coords.

darktable-org/rawspeed,LebedevRI/rawspeed,LebedevRI/rawspeed,LebedevRI/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed,darktable-org/rawspeed,darktable-org/rawspeed