add support for gsm0808 HANDOVER REQUIRED message

Related: OS#2283 (inter-BSC Handover, BSC side, MO)
Change-Id: Idb6dc3eab0282158a17091d97ed77c1e2e3eb3c2
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index 5a57429..58a5bfe 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -161,6 +161,7 @@
 gsm0808_create_reset;
 gsm0808_create_reset_ack;
 gsm0808_create_sapi_reject;
+gsm0808_create_handover_required;
 gsm0808_prepend_dtap_header;
 gsm0808_enc_aoip_trasp_addr;
 gsm0808_dec_aoip_trasp_addr;