Avoid unused param warnings in c_ares directory

src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc

@@ -99,7 +99,8 @@ class GrpcPolledFdFactoryPosix : public GrpcPolledFdFactory {
 };
 
 std::unique_ptr<GrpcPolledFdFactory> NewGrpcPolledFdFactory(
-    std::shared_ptr<WorkSerializer> work_serializer) { /* NOLINT */
+    std::shared_ptr<WorkSerializer> work_serializer) {
+  (void)work_serializer;
   return absl::make_unique<GrpcPolledFdFactoryPosix>();
 }
 

src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc

@@ -619,7 +619,7 @@ static bool grpc_ares_maybe_resolve_localhost_manually_locked(
 }
 #else  /* GRPC_ARES_RESOLVE_LOCALHOST_MANUALLY */
 static bool grpc_ares_maybe_resolve_localhost_manually_locked(
-    const grpc_ares_request* r, const char* /*name*/,
+    const grpc_ares_request* /*r*/, const char* /*name*/,
     const char* /*default_port*/,
     std::unique_ptr<grpc_core::ServerAddressList>* /*addrs*/) {
   return false;