SEBA-566 Add linting and fix errors in fabric-crossconnect

Change-Id: I6c7bfd15e3b7d61d3d0bde7798a825b23780dcf2
diff --git a/xos/synchronizer/models/fabric-crossconnect.xproto b/xos/synchronizer/models/fabric-crossconnect.xproto
index d908092..0d8fc45 100644
--- a/xos/synchronizer/models/fabric-crossconnect.xproto
+++ b/xos/synchronizer/models/fabric-crossconnect.xproto
@@ -25,6 +25,7 @@
 message BNGPortMapping (XOSBase) {
     required string s_tag = 1 [
         help_text = "Single s-tag, range of s-tags, or 'ANY'",
+        max_length = 1024,
         tosca_key = True,
         unique = True];
     required int32 switch_port = 2 [