[sensorservice] Modernize codebase by replacing NULL with nullptr

Fixes -Wzero-as-null-pointer-constant warning.

Test: m
Bug: 68236239
Change-Id: I9938306410e9773243b2b9c5e2fc4afdb48b9810
diff --git a/services/sensorservice/BatteryService.cpp b/services/sensorservice/BatteryService.cpp
index d8e5b29..14f9a12 100644
--- a/services/sensorservice/BatteryService.cpp
+++ b/services/sensorservice/BatteryService.cpp
@@ -94,7 +94,7 @@
 bool BatteryService::checkService() {
     if (mBatteryStatService == nullptr) {
         const sp<IServiceManager> sm(defaultServiceManager());
-        if (sm != NULL) {
+        if (sm != nullptr) {
             const String16 name("batterystats");
             mBatteryStatService = interface_cast<IBatteryStats>(sm->getService(name));
         }