Added missing parameters for updates repo.

Change-Id: Ib1645825650539aa419be47ddb205b2875008d8a
diff --git a/init.yml b/init.yml
index 506c53d..e376f9b 100644
--- a/init.yml
+++ b/init.yml
@@ -140,11 +140,15 @@
       repo:
         mcp_xenial_updates:
           component: updates
+          architectures: amd64
+          comment: "Local Xenial updates repository."
           distributions:
             - ubuntu-xenial/${_param:apt_mk_version}
             - ubuntu-xenial/stable
         mcp_trusty_updates:
           component: updates
+          architectures: amd64
+          comment: "Local Trusty updates repository."
           distributions:
             - ubuntu-trusty/${_param:apt_mk_version}
             - ubuntu-trusty/stable