native frameworks: 64-bit compile issues

- Fix format (print/scanf)
- Suppress unused argument warning messages (bonus)

Change-Id: I05c7724d2aba6da1e82a86000e11f3a8fef4e728
diff --git a/services/sensorservice/main_sensorservice.cpp b/services/sensorservice/main_sensorservice.cpp
index 303b65f..0a96f42 100644
--- a/services/sensorservice/main_sensorservice.cpp
+++ b/services/sensorservice/main_sensorservice.cpp
@@ -19,7 +19,7 @@
 
 using namespace android;
 
-int main(int argc, char** argv) {
+int main(int /*argc*/, char** /*argv*/) {
     SensorService::publishAndJoinThreadPool();
     return 0;
 }