Fixing unused param warnings in sync_test

Change-Id: Ia37a0118397ddece376bfbad7627d83263c1993f
Author: Edwin Vane <edwin.vane@intel.com>
Reviewed-by: Kevin P Schoedel <kevin.p.schoedel@intel.com>

libsync/sync_test.c

@@ -72,7 +72,7 @@ void *sync_thread(void *data)
     return NULL;
 }
 
-int main(int argc, char *argv[])
+int main(int argc __attribute__((unused)), char *argv[] __attribute__((unused)))
 {
     struct sync_thread_data sync_data[4];
     pthread_t threads[4];