Add GSUP_CN_DOMAIN_* defines

Change-Id: Ic5790e6984bfdb993ac0586b9dbc4c769e54e90e
diff --git a/include/gsup_protocol.hrl b/include/gsup_protocol.hrl
index 10f62ff..adc78d7 100644
--- a/include/gsup_protocol.hrl
+++ b/include/gsup_protocol.hrl
@@ -25,6 +25,9 @@
 -define(GSUP_CANCELLATION_TYPE_UPDATE, 16#00).
 -define(GSUP_CANCELLATION_TYPE_WITHDRAW, 16#01).
 
+-define(GSUP_CN_DOMAIN_PS, 16#01).
+-define(GSUP_CN_DOMAIN_CS, 16#02).
+
 -type 'GSUPMessageType'() :: location_upd_req
                   | location_upd_err
                   | location_upd_res