NITF: fix to support reading horizontal and/or vertical mono-block uncompressed images, even when the number of columns is <= 8192 (#3263)

git-svn-id: https://svn.osgeo.org/gdal/trunk@26188 f0d54148-0727-0410-94bb-9a71ac55c965
Merge branch 'trunk' of github.com:rouault/gdal into trunk_with_coverage