[MLIR] Apply clang-tidy fixes for performance-unnecessary-value-param in IRTypes.cpp (NFC)

Author: joker-eph

mlir/lib/Bindings/Python/IRTypes.cpp

@@ -963,7 +963,7 @@ class PyOpaqueType : public PyConcreteType<PyOpaqueType> {
   static void bindDerived(ClassTy &c) {
     c.def_static(
         "get",
-        [](std::string dialectNamespace, std::string typeData,
+        [](const std::string &dialectNamespace, const std::string &typeData,
            DefaultingPyMlirContext context) {
           MlirType type = mlirOpaqueTypeGet(context->get(),
                                             toMlirStringRef(dialectNamespace),