Set elapsedRealtime if HAL doesn't set it

Bug: 246631036
Test: manual
Change-Id: Ifefcf1448bcf59cddcf9f9aaaf4a0571030544ec
diff --git a/services/core/jni/gnss/Utils.cpp b/services/core/jni/gnss/Utils.cpp
index 8f32c47..571534f 100644
--- a/services/core/jni/gnss/Utils.cpp
+++ b/services/core/jni/gnss/Utils.cpp
@@ -195,6 +195,8 @@
     flags = static_cast<uint32_t>(location.elapsedRealtime.flags);
     if (flags & android::hardware::gnss::ElapsedRealtime::HAS_TIMESTAMP_NS) {
         SET(ElapsedRealtimeNanos, location.elapsedRealtime.timestampNs);
+    } else {
+        SET(ElapsedRealtimeNanos, android::elapsedRealtimeNano());
     }
     if (flags & android::hardware::gnss::ElapsedRealtime::HAS_TIME_UNCERTAINTY_NS) {
         SET(ElapsedRealtimeUncertaintyNanos,