[mlir][openacc][NFC] Fix verifier message

[vzakhari]

LGTM

[clementval]

clang-format

mlir/lib/Dialect/OpenACC/IR/OpenACC.cpp

for (auto args : llvm::zip(operands, *attributes)) {
     auto symbolRef = std::get<1>(args).cast<SymbolRefAttr>();
     auto decl = SymbolTable::lookupNearestSymbolFrom<Op>(op, symbolRef);
     if (!decl)
       return op->emitOpError()
              << "expected symbol reference " << symbolRef << " to point to a "
              << operandName << " declaration";
 
     if (decl.getType() && decl.getType() != varType)
-      return op->emitOpError()
-             << "expected private (" << varType << ") to be the same type as "
-             << operandName << " declaration (" << decl.getType() << ")";
+      return op->emitOpError() << "expected " << operandName << " (" << varType
+                               << ") to be the same type as " << operandName
+                               << " declaration (" << decl.getType() << ")";
   }
 
   return success();
 }
 
 unsigned ParallelOp::getNumDataOperands() {
   return getReductionOperands().size() + getGangPrivateOperands().size() +
          getGangFirstPrivateOperands().size() + getDataClauseOperands().size();