Fix the error spotted by meson

- This commit would fix the error that are spotted by meson
  when werror=true is enforced.

Tested By:

- Compiled in all the sdks, and unit tests are passed.

Signed-off-by: Manojkiran Eda <manojkiran.eda@gmail.com>
Change-Id: Ie4c2f26af2b62b019e908cceea18cf22cf2e4607
diff --git a/rtnetlink_server.cpp b/rtnetlink_server.cpp
index 1c4fd53..07ca08c 100644
--- a/rtnetlink_server.cpp
+++ b/rtnetlink_server.cpp
@@ -56,8 +56,8 @@
 }
 
 /* Call Back for the sd event loop */
-static int eventHandler(sd_event_source* es, int fd, uint32_t revents,
-                        void* userdata)
+static int eventHandler(sd_event_source* /*es*/, int fd, uint32_t /*revents*/,
+                        void* /*userdata*/)
 {
     char buffer[phosphor::network::rtnetlink::BUFSIZE]{};
     int len{};