Use -Werror in hardware/interfaces

* Remove unused local variables.

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: I48dbbf670cc9eeff2391983788983420f8547cc9
diff --git a/tests/msgq/1.0/default/Android.bp b/tests/msgq/1.0/default/Android.bp
index eb25ac2..be4fe94 100644
--- a/tests/msgq/1.0/default/Android.bp
+++ b/tests/msgq/1.0/default/Android.bp
@@ -35,6 +35,7 @@
 
 cc_test {
     name: "android.hardware.tests.msgq@1.0-service-benchmark",
+    defaults: ["hidl_defaults"],
     srcs: ["mq_benchmark_service.cpp"],
     gtest: false,
 
@@ -51,6 +52,7 @@
 
 cc_test {
     name: "android.hardware.tests.msgq@1.0-service-test",
+    defaults: ["hidl_defaults"],
     srcs: ["mq_test_service.cpp"],
     gtest: false,