[coverity] fix coverity issue

Fix coverity issue on
- /test/unittest/layers/layers_golden_recurrent.cpp

The other issues assigned have already been fixed.

**Self evaluation:**
1. Build test:	 [X]Passed [ ]Failed [ ]Skipped
2. Run test:	 [X]Passed [ ]Failed [ ]Skipped

Signed-off-by: Seungbaek Hong <sb92.hong@samsung.com>

test/unittest/models/unittest_models_recurrent.cpp

@@ -673,6 +673,5 @@ GTEST_PARAMETER_TEST(
                  ModelTestOption::ALL_V2),
     mkModelTc_V2(makeStackedGRUCellFC, "grucell_fc", ModelTestOption::ALL_V2),
   }),
-  [](const testing::TestParamInfo<nntrainerModelTest::ParamType> &info) {
-    return std::get<1>(info.param);
-  });
+  [](const testing::TestParamInfo<nntrainerModelTest::ParamType> &info)
+    -> const auto & { return std::get<1>(info.param); });