adding EthType to secure handling ether types

this will also pretty print ethertypes in flow output

Change-Id: I9363070ad308f3c756735e29b3992c500e503636
diff --git a/drivers/src/main/java/org/onosproject/driver/pipeline/SpringOpenTTPDell.java b/drivers/src/main/java/org/onosproject/driver/pipeline/SpringOpenTTPDell.java
index f68a665..3267d550 100644
--- a/drivers/src/main/java/org/onosproject/driver/pipeline/SpringOpenTTPDell.java
+++ b/drivers/src/main/java/org/onosproject/driver/pipeline/SpringOpenTTPDell.java
@@ -81,8 +81,8 @@
         EthTypeCriterion ethType = (EthTypeCriterion) selector
                 .getCriterion(Criterion.Type.ETH_TYPE);
         if ((ethType == null) ||
-                ((((short) ethType.ethType()) != Ethernet.TYPE_IPV4) &&
-                (((short) ethType.ethType()) != Ethernet.MPLS_UNICAST))) {
+                (ethType.ethType().toShort() != Ethernet.TYPE_IPV4) &&
+                (ethType.ethType().toShort() != Ethernet.MPLS_UNICAST)) {
             log.debug("processSpecific: Unsupported "
                     + "forwarding objective criteraia");
             fail(fwd, ObjectiveError.UNSUPPORTED);
@@ -92,7 +92,7 @@
         TrafficSelector.Builder filteredSelectorBuilder =
                 DefaultTrafficSelector.builder();
         int forTableId = -1;
-        if (((short) ethType.ethType()) == Ethernet.TYPE_IPV4) {
+        if (ethType.ethType().toShort() == Ethernet.TYPE_IPV4) {
             if (deviceTMac == null) {
                 log.debug("processSpecific: ETH_DST filtering "
                         + "objective is not set which is required "