avoid compiler warning

Author: Meinersbur

flang/lib/Lower/OpenMP/Utils.cpp

@@ -652,7 +652,6 @@ int64_t collectLoopRelatedInfo(
     mlir::omp::LoopRelatedClauseOps &result,
     llvm::SmallVectorImpl<const semantics::Symbol *> &iv) {
   int64_t numCollapse = 1;
-  fir::FirOpBuilder &firOpBuilder = converter.getFirOpBuilder();
 
   // Collect the loops to collapse.
   lower::pft::Evaluation *doConstructEval = &eval.getFirstNestedEvaluation();