Removed extra string instance creation

According to the auto-generated code the reverseDomainName
is a android::hardware::hidl_string which follow RAII approach
Similar to std::string

Bug: 212755214
Test: aidl_stats_client
Change-Id: I2fe90721a56abcbf20586e17550304be608de21b
diff --git a/services/stats/StatsHal.cpp b/services/stats/StatsHal.cpp
index ae0a984..d27d989 100644
--- a/services/stats/StatsHal.cpp
+++ b/services/stats/StatsHal.cpp
@@ -112,13 +112,13 @@
 }
 
 hardware::Return<void> StatsHal::reportVendorAtom(const VendorAtom& vendorAtom) {
-    std::string reverseDomainName = (std::string) vendorAtom.reverseDomainName;
     if (vendorAtom.atomId < 100000 || vendorAtom.atomId >= 200000) {
         ALOGE("Atom ID %ld is not a valid vendor atom ID", (long) vendorAtom.atomId);
         return hardware::Void();
     }
-    if (reverseDomainName.length() > 50) {
-        ALOGE("Vendor atom reverse domain name %s is too long.", reverseDomainName.c_str());
+    if (vendorAtom.reverseDomainName.size() > 50) {
+        ALOGE("Vendor atom reverse domain name %s is too long.",
+              vendorAtom.reverseDomainName.c_str());
         return hardware::Void();
     }
     AStatsEvent* event = AStatsEvent_obtain();