[ONOS-4753] Identity/identityref implementation and UT

Change-Id: I40148fa228465555be3bdf410cc294ffc0f34c18
diff --git a/utils/yangutils/plugin/src/main/java/org/onosproject/yangutils/linker/impl/YangLinkerManager.java b/utils/yangutils/plugin/src/main/java/org/onosproject/yangutils/linker/impl/YangLinkerManager.java
index 914b5d5..3847d3d 100644
--- a/utils/yangutils/plugin/src/main/java/org/onosproject/yangutils/linker/impl/YangLinkerManager.java
+++ b/utils/yangutils/plugin/src/main/java/org/onosproject/yangutils/linker/impl/YangLinkerManager.java
@@ -158,11 +158,16 @@
             try {
                 ((YangReferenceResolver) yangNode)
                         .resolveInterFileLinking(ResolvableType.YANG_IF_FEATURE);
-                ((YangReferenceResolver) yangNode).resolveInterFileLinking(ResolvableType.YANG_USES);
+                ((YangReferenceResolver) yangNode)
+                        .resolveInterFileLinking(ResolvableType.YANG_USES);
                 ((YangReferenceResolver) yangNode)
                         .resolveInterFileLinking(ResolvableType.YANG_DERIVED_DATA_TYPE);
                 ((YangReferenceResolver) yangNode)
                         .resolveInterFileLinking(ResolvableType.YANG_LEAFREF);
+                ((YangReferenceResolver) yangNode)
+                        .resolveInterFileLinking(ResolvableType.YANG_BASE);
+                ((YangReferenceResolver) yangNode)
+                        .resolveInterFileLinking(ResolvableType.YANG_IDENTITYREF);
             } catch (DataModelException e) {
                 String errorInfo = "Error in file: " + yangNode.getName() + " at line: "
                         + e.getLineNumber() + " at position: " + e.getCharPositionInLine() + NEW_LINE + e.getMessage();