gprs_ns2: use llist_add_tail to keep order

When configuring multiple NSE/BINDs the order of the configuration
should be keeped.

Related: OS#5181
Change-Id: Ibbc03f0780b49543b5bd97ee059f11cfd6c2a126
diff --git a/src/gb/gprs_ns2_vty.c b/src/gb/gprs_ns2_vty.c
index 2777641..705b60e 100644
--- a/src/gb/gprs_ns2_vty.c
+++ b/src/gb/gprs_ns2_vty.c
@@ -141,7 +141,7 @@
 
 	vbind->ip_sns_sig_weight = 1;
 	vbind->ip_sns_data_weight = 1;
-	llist_add(&vbind->list, &binds);
+	llist_add_tail(&vbind->list, &binds);
 	return vbind;
 }
 
@@ -172,7 +172,7 @@
 
 	vnse->nsei = nsei;
 	INIT_LLIST_HEAD(&vnse->binds);
-	llist_add(&vnse->list, &nses);
+	llist_add_tail(&vnse->list, &nses);
 	return vnse;
 }