GTiff: make SetColorInterpretation() round-trip with GetColorInterpreation(); read color interpretation from PAM if it exists (overrides internal tiff color interpretation); set TIFFTAG_PHOTOMETRIC=PHOTOMETRIC_RGB if calling SetColorInterpretation() with R,G,B and no explicit PHOTOMETRIC creation option defined

git-svn-id: https://svn.osgeo.org/gdal/trunk/gdal@26674 f0d54148-0727-0410-94bb-9a71ac55c965