NITF: Support for cases with 2 LUTs (adapted from 1.8-esri r25754. didn't merge then change in RPC handling since trunk is too different from 1.8-esri)

git-svn-id: https://svn.osgeo.org/gdal/trunk@25777 f0d54148-0727-0410-94bb-9a71ac55c965