SensorService: Fix some warnings

For build-system CFLAGS clean-up, remove unused variables.

Also fix some warnings related to format strings, and signed
comparisons.

Bug: 18632512
Change-Id: I5e48dce36678c12069c0e162b920870de81b89f2
diff --git a/services/sensorservice/SensorDevice.cpp b/services/sensorservice/SensorDevice.cpp
index dd1bccf..40d596f 100644
--- a/services/sensorservice/SensorDevice.cpp
+++ b/services/sensorservice/SensorDevice.cpp
@@ -388,7 +388,7 @@
 
 status_t SensorDevice::injectSensorData(const sensors_event_t *injected_sensor_event) {
       ALOGD_IF(DEBUG_CONNECTIONS,
-              "sensor_event handle=%d ts=%lld data=%.2f, %.2f, %.2f %.2f %.2f %.2f",
+              "sensor_event handle=%d ts=%" PRId64 " data=%.2f, %.2f, %.2f %.2f %.2f %.2f",
                injected_sensor_event->sensor,
                injected_sensor_event->timestamp, injected_sensor_event->data[0],
                injected_sensor_event->data[1], injected_sensor_event->data[2],