Fixing javadocs.

Change-Id: I9e6b3d7eb08d17d4ad450277a1279f6aaefd4640
diff --git a/core/api/src/main/java/org/onosproject/net/device/DefaultPortStatistics.java b/core/api/src/main/java/org/onosproject/net/device/DefaultPortStatistics.java
index 93c91ce..0382833 100644
--- a/core/api/src/main/java/org/onosproject/net/device/DefaultPortStatistics.java
+++ b/core/api/src/main/java/org/onosproject/net/device/DefaultPortStatistics.java
@@ -248,7 +248,7 @@
         /**
          * Sets the number of packets dropped by TX.
          *
-         * @param packets
+         * @param packets number of packets
          * @return builder object
          */
         public Builder setPacketsTxDropped(long packets) {