enb: Add attribute to set 'id'

Change-Id: I8ce296c7875d557062dc13e7093ce0400050f2ce
diff --git a/sysmocom/defaults.conf b/sysmocom/defaults.conf
index bf5bce1..aea2791 100644
--- a/sysmocom/defaults.conf
+++ b/sysmocom/defaults.conf
@@ -106,6 +106,7 @@
   license_server_addr: 0.0.0.0
 
 enb:
+  id: 0x19B
   mcc: 901
   mnc: 70
   transmission_mode: 1