[ONOS-6473] Refactor getPhysicalDevices method in VirtualNetworkService

Change-Id: I3f4549f3ea630283d72a1df1e59f24f33df1b672
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/VirtualNetworkService.java b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/VirtualNetworkService.java
index da791de..88ef56b 100644
--- a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/VirtualNetworkService.java
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/VirtualNetworkService.java
@@ -90,11 +90,10 @@
      * port mapping mechanism.
      *
      * @param networkId network identifier
-     * @param virtualDevice the virtual device
+     * @param deviceId the virtual device identifier
      * @return collection of the specified device's identifier
      */
-    Set<DeviceId> getPhysicalDevices(NetworkId networkId,
-                                             VirtualDevice virtualDevice);
+    Set<DeviceId> getPhysicalDevices(NetworkId networkId, DeviceId deviceId);
 
     /**
      * Returns implementation of the specified service class for operating