iu_client: introduce ranap_iu_free_ue() to free the UE connections

When freeing the UE connection object, disconnect the SCCP connection.

Change-Id: I6812edb4da487507ccf9f483de801c1c65c4b72b
diff --git a/src/iu_client.c b/src/iu_client.c
index ce06f8a..c7ed341 100644
--- a/src/iu_client.c
+++ b/src/iu_client.c
@@ -131,6 +131,16 @@
 	return NULL;
 }
 
+void ranap_iu_free_ue(struct ranap_ue_conn_ctx *ue_ctx)
+{
+	if (!ue_ctx)
+		return;
+
+	osmo_sccp_tx_disconn(g_scu, ue_ctx->conn_id, NULL, 0);
+	llist_del(&ue_ctx->list);
+	talloc_free(ue_ctx);
+}
+
 static struct ranap_iu_rnc *iu_rnc_alloc(uint16_t rnc_id, struct osmo_sccp_addr *addr)
 {
 	struct ranap_iu_rnc *rnc = talloc_zero(talloc_iu_ctx, struct ranap_iu_rnc);