[CORD-2711]
Use hardcoded fabric MAC address

Change-Id: I4ce29d40dcad030116f06f767c36445b38c7f514
(cherry picked from commit 553f140109fa1a19716162c6eb02a50c0949e1c9)
diff --git a/roles/interface-config/defaults/main.yml b/roles/interface-config/defaults/main.yml
index c1cdad0..6e2b541 100644
--- a/roles/interface-config/defaults/main.yml
+++ b/roles/interface-config/defaults/main.yml
@@ -25,6 +25,10 @@
 management_net_interfaces: []
 fabric_net_interfaces: []
 
+# The following value is hardcoded and should be identical to here:
+# https://github.com/opencord/maas/blob/master/config-generator/netconfig.tpl#L29
+fabric_gateway_hwaddr: "a4:23:05:06:01:01"
+
 # management network configuration
 management_net_cidr: "10.1.0.0/24"
 management_net_bridge: "mgmtbr"