Update docs for proper cloud-init data

Change-Id: I0a4066a1e2c8fe2a660d921e709539d51592ee5e
diff --git a/README.rst b/README.rst
index b89cb51..2e62556 100644
--- a/README.rst
+++ b/README.rst
@@ -411,6 +411,10 @@
 .. code-block:: yaml
 
     _param:
+      vcp_links: &vcp_links
+      - type: phy
+        id: ens2
+        name: ens2
       private-ipv4: &private-ipv4
       - id: private-ipv4
         type: ipv4
@@ -515,6 +519,7 @@
                 # manual interfaces configuration
                 cloud_init:
                   network_data:
+                    links: *vcp_links
                     networks:
                     - <<: *private-ipv4
                       ip_address: 192.168.0.161