Initialize uninitialized member in BatteryService

A field was left uninitialized, which could lead to undefined behavior.

Test: Builds, boots, sensor events show up in BatteryStats as expected.

Bug: 275436924
Change-Id: I42e42356980d75d563be763d60f56bedb863bc33
diff --git a/services/sensorservice/BatteryService.cpp b/services/sensorservice/BatteryService.cpp
index b0fbe5d..0ea548c 100644
--- a/services/sensorservice/BatteryService.cpp
+++ b/services/sensorservice/BatteryService.cpp
@@ -30,8 +30,8 @@
 namespace android {
 // ---------------------------------------------------------------------------
 
-BatteryService::BatteryService() : mBatteryStatService(nullptr) {
-}
+BatteryService::BatteryService()
+    : mBatteryStatService(nullptr), mLastWakeupSensorEventReportedMs(0) {}
 
 bool BatteryService::addSensor(uid_t uid, int handle) {
     Mutex::Autolock _l(mActivationsLock);