hnbgw_cn.c: fix uninitialized hnb_gw pointer

In cn_ranap_rx_paging_cmd(), actually initialize the gw var.

Upon creation of an hnbgw_cnlink, actually set hnbgw_cnlink->gw.
diff --git a/src/hnbgw_cn.c b/src/hnbgw_cn.c
index 029038e..60c40c7 100644
--- a/src/hnbgw_cn.c
+++ b/src/hnbgw_cn.c
@@ -127,7 +127,7 @@
 				  RANAP_InitiatingMessage_t *imsg,
 				  const uint8_t *data, unsigned int len)
 {
-	struct hnb_gw *gw;
+	struct hnb_gw *gw = cnlink->gw;
 	struct hnb_context *hnb;
 	RANAP_PagingIEs_t ies;
 	int rc = 0;
@@ -368,6 +368,7 @@
 	struct hnbgw_cnlink *cnlink = talloc_zero(gw, struct hnbgw_cnlink);
 	int rc;
 
+	cnlink->gw = gw;
 	INIT_LLIST_HEAD(&cnlink->map_list);
 	cnlink->T_RafC.cb = cnlink_trafc_cb;
 	cnlink->T_RafC.data = cnlink;