Allow multiple registrator to register classes

Change-Id: I35a56b889c45b936bb022a9639702fda21619258
diff --git a/runtime/src/main/java/org/onosproject/yang/runtime/impl/DefaultYangModelRegistry.java b/runtime/src/main/java/org/onosproject/yang/runtime/impl/DefaultYangModelRegistry.java
index 09cc1e0..b58986e 100644
--- a/runtime/src/main/java/org/onosproject/yang/runtime/impl/DefaultYangModelRegistry.java
+++ b/runtime/src/main/java/org/onosproject/yang/runtime/impl/DefaultYangModelRegistry.java
@@ -150,8 +150,7 @@
         if (!modelIdStore.containsKey(id)) {
             updateRegClassStore(param);
             modelIdStore.put(id, model);
-        } else if ((info != null) &&
-                   (!registerClassStore.containsValue(info.getModuleClass()))) {
+        } else if (info != null) {
             updateRegClassStore(param);
         } else {
             throw new IllegalArgumentException("ModelId " + id + " already exist");