[sensor] Modernize codebase by replacing NULL with nullptr

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

Test: m
Bug: 68236239
Change-Id: I82e6ef0f074571a9537fa2eeedf56975363ca601
diff --git a/libs/sensor/Sensor.cpp b/libs/sensor/Sensor.cpp
index a0e368c..d9a986e 100644
--- a/libs/sensor/Sensor.cpp
+++ b/libs/sensor/Sensor.cpp
@@ -318,7 +318,7 @@
         // If the sensor is protected by a permission we need to know if it is
         // a runtime one to determine whether we can use the permission cache.
         sp<IBinder> binder = defaultServiceManager()->getService(String16("permission"));
-        if (binder != 0) {
+        if (binder != nullptr) {
             sp<IPermissionController> permCtrl = interface_cast<IPermissionController>(binder);
             mRequiredPermissionRuntime = permCtrl->isRuntimePermission(
                     String16(mRequiredPermission));