ENH: use Pstream::subProc() to simplify code

src/runTimePostProcessing/geometryCloudGather.C

src/runTimePostProcessing/geometryCloudTemplates.C

src/runTimePostProcessing/geometryPatchesGather.C

src/runTimePostProcessing/geometryPatchesTemplates.C

src/runTimePostProcessing/surfaceGather.C

src/runTimePostProcessing/surfaceTemplates.C