Enable wakeup sensors.

SensorService should hold a wakelock till the app reads events from a wakeup sensor. Currently drivers hold a wakelock with a
timeout while delivering events from a wake up sensor like Significant Motion. This hack can be removed now.

Bug: 9774884
Change-Id: If3b5acb99c9cf0cd29012fcfa9d6b04c74133d01
diff --git a/services/sensorservice/SensorDevice.cpp b/services/sensorservice/SensorDevice.cpp
index 3b64f0a..01dbdfb 100644
--- a/services/sensorservice/SensorDevice.cpp
+++ b/services/sensorservice/SensorDevice.cpp
@@ -309,7 +309,7 @@
     return mSensorDevice->common.version;
 }
 
-status_t SensorDevice::flush(void* /*ident*/, int handle) {
+status_t SensorDevice::flush(void* ident, int handle) {
     if (getHalDeviceVersion() < SENSORS_DEVICE_API_VERSION_1_1) {
         return INVALID_OPERATION;
     }