Sonar fixes

Rule: Use isEmpty() to check whether the collection is empty or not.

Change-Id: Ib5ab56b2263623b297db56c5cac2c2ee80e12725
diff --git a/src/main/java/org/onosproject/segmentrouting/config/DeviceConfiguration.java b/src/main/java/org/onosproject/segmentrouting/config/DeviceConfiguration.java
index 7eb6894..2bd9932 100644
--- a/src/main/java/org/onosproject/segmentrouting/config/DeviceConfiguration.java
+++ b/src/main/java/org/onosproject/segmentrouting/config/DeviceConfiguration.java
@@ -357,7 +357,7 @@
                         .map(IpPrefix::getIp4Prefix)
                         .collect(Collectors.toSet());
 
-        if (subnets.size() == 0) {
+        if (subnets.isEmpty()) {
             log.info(NO_SUBNET, connectPoint);
             return null;
         } else if (subnets.size() > 1) {