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/tests/gb/gprs_ns2_vty.vty b/tests/gb/gprs_ns2_vty.vty
index 891bde5..4589f96 100644
--- a/tests/gb/gprs_ns2_vty.vty
+++ b/tests/gb/gprs_ns2_vty.vty
@@ -54,15 +54,15 @@
 OsmoNSdummy# show ns
 NSEI 01234: UDP, DEAD
   3 NS-VC:
-   NSVCI none: RECOVERING PERSIST data_weight=0 sig_weight=0 udp)[127.0.0.14]:42999<>[127.0.0.17]:9496
-   NSVCI none: RECOVERING PERSIST data_weight=9 sig_weight=0 udp)[127.0.0.14]:42999<>[127.0.0.16]:9496
    NSVCI none: RECOVERING PERSIST data_weight=1 sig_weight=1 udp)[127.0.0.14]:42999<>[127.0.0.15]:9496
+   NSVCI none: RECOVERING PERSIST data_weight=9 sig_weight=0 udp)[127.0.0.14]:42999<>[127.0.0.16]:9496
+   NSVCI none: RECOVERING PERSIST data_weight=0 sig_weight=0 udp)[127.0.0.14]:42999<>[127.0.0.17]:9496
 UDP bind: 127.0.0.14:42999 DSCP: 0 Priority: 0
   IP-SNS signalling weight: 1 data weight: 1
   3 NS-VC:
-   NSVCI none: RECOVERING PERSIST data_weight=0 sig_weight=0 udp)[127.0.0.14]:42999<>[127.0.0.17]:9496
-   NSVCI none: RECOVERING PERSIST data_weight=9 sig_weight=0 udp)[127.0.0.14]:42999<>[127.0.0.16]:9496
    NSVCI none: RECOVERING PERSIST data_weight=1 sig_weight=1 udp)[127.0.0.14]:42999<>[127.0.0.15]:9496
+   NSVCI none: RECOVERING PERSIST data_weight=9 sig_weight=0 udp)[127.0.0.14]:42999<>[127.0.0.16]:9496
+   NSVCI none: RECOVERING PERSIST data_weight=0 sig_weight=0 udp)[127.0.0.14]:42999<>[127.0.0.17]:9496
 OsmoNSdummy# configure terminal
 OsmoNSdummy(config)# ns
 OsmoNSdummy(config-ns)# nse 1234