AETHER-3189 Update ids to be dns compliant:

Change-Id: Ic03b51c62fb205a5505a15e743f93b0057f9b93b
diff --git a/config-models/aether-2.0.x/files/yang/onf-enterprise.yang b/config-models/aether-2.0.x/files/yang/onf-enterprise.yang
index 00334f9..61a453e 100755
--- a/config-models/aether-2.0.x/files/yang/onf-enterprise.yang
+++ b/config-models/aether-2.0.x/files/yang/onf-enterprise.yang
@@ -6,7 +6,6 @@
   namespace "http://opennetworking.org/aether/enterprise";
   prefix ent;
 
-  import ietf-yang-types{ prefix yg; }
   import onf-aether-types { prefix at; }
   import onf-connectivity-service { prefix cs; }
 
@@ -44,10 +43,8 @@
   }
 
   typedef enterprise-id {
-        type yg:yang-identifier {
-            length 1..32;
-        }
-   description "The typedef for enterprise-id";
+     type at:aether-identifier;
+     description "The typedef for enterprise-id";
   }
 
   container enterprises {