osmo-bsc: Print NOTICE message on unimplemented BSSMAP UDT

When we receive unimplemented/unhandled message types, we shouldn't
simply silently discard them, but print a log message for the
benefit of the user.

Change-Id: I65489578b1c214f193b1ce0e9ba59432dcd42a3e

src/osmo-bsc/osmo_bsc_bssap.c

@@ -645,6 +645,10 @@ static int bssmap_rcvmsg_udt(struct bsc_msc_data *msc,
 	case BSS_MAP_MSG_PAGING:
 		ret = bssmap_handle_paging(msc, msg, length);
 		break;
+	default:
+		LOGP(DMSC, LOGL_NOTICE, "Received unimplemented BSSMAP UDT %s\n",
+			gsm0808_bssmap_name(msg->l4h[0]));
+		break;
 	}
 
 	return ret;