Adding helper method in RADIUS packet

Change-Id: Ia4641a89699ffbc2dd1a591f323829399b728e6b
diff --git a/utils/misc/src/main/java/org/onlab/packet/RADIUS.java b/utils/misc/src/main/java/org/onlab/packet/RADIUS.java
index 3f3b517..0553b91 100644
--- a/utils/misc/src/main/java/org/onlab/packet/RADIUS.java
+++ b/utils/misc/src/main/java/org/onlab/packet/RADIUS.java
@@ -105,6 +105,15 @@
     }
 
     /**
+     * Get the identifier in a readable format.
+     *
+     * @return identifier
+     */
+    public int getReadableIdentifier() {
+        return this.identifier & 0xff;
+    }
+
+    /**
      * Sets the identifier.
      *
      * @param identifier identifier