Add sdk-port annotation with discover port from Stratum

Change-Id: I37f810767df9fb5adee815cd19e78c71a1aaa37c
diff --git a/drivers/gnmi/src/main/java/org/onosproject/drivers/gnmi/OpenConfigGnmiDeviceDescriptionDiscovery.java b/drivers/gnmi/src/main/java/org/onosproject/drivers/gnmi/OpenConfigGnmiDeviceDescriptionDiscovery.java
index ee7ccc5..6ae4c33 100644
--- a/drivers/gnmi/src/main/java/org/onosproject/drivers/gnmi/OpenConfigGnmiDeviceDescriptionDiscovery.java
+++ b/drivers/gnmi/src/main/java/org/onosproject/drivers/gnmi/OpenConfigGnmiDeviceDescriptionDiscovery.java
@@ -58,6 +58,7 @@
             .getLogger(OpenConfigGnmiDeviceDescriptionDiscovery.class);
 
     private static final String LAST_CHANGE = "last-change";
+    private static final String SDK_PORT = "sdk-port";
 
     private static final String UNKNOWN = "unknown";
 
@@ -170,6 +171,7 @@
             switch (pathElemName) {
                 case "ifindex": // port number
                     builder.withPortNumber(PortNumber.portNumber(val.getUintVal(), ifName));
+                    annotationsBuilder.set(SDK_PORT, String.valueOf(val.getUintVal()));
                     return;
                 case "oper-status":
                     builder.isEnabled(parseOperStatus(val.getStringVal()));