EmbreManager: fix Wsign-compare
Fixes this warning:
/<<PKGBUILDDIR>>/source/EmbreeManager.cpp: In member function ‘vecgeom::cxx::EmbreeManager::EmbreeAccelerationStructure* vecgeom::cxx::EmbreeManager::BuildStructureFromBoundingBoxes(const vecgeom::cxx::LogicalVolume*) const’:
/<<PKGBUILDDIR>>/source/EmbreeManager.cpp:82:21: warning: comparison of integer expressions of different signedness: ‘int’ and ‘const long unsigned int’ [-Wsign-compare]
82 | for (int d = 0; d < numberofdaughters; ++d) {
| ~~^~~~~~~~~~~~~~~~~~~
/<<PKGBUILDDIR>>/source/EmbreeManager.cpp: In member function ‘vecgeom::cxx::EmbreeManager::EmbreeAccelerationStructure* vecgeom::cxx::EmbreeManager::BuildStructureFromBoundingBoxes(vecgeom::cxx::ABBoxManager::ABBox_s*, size_t) const’:
/<<PKGBUILDDIR>>/source/EmbreeManager.cpp:115:21: warning: comparison of integer expressions of different signedness: ‘int’ and ‘size_t’ {aka ‘long unsigned int’} [-Wsign-compare]
115 | for (int d = 0; d < numberofdaughters; ++d) {
| ~~^~~~~~~~~~~~~~~~~~~