print OML bts_nr rather than bts->nr

diff --git a/src/gsm_data.c b/src/gsm_data.c
index 136f31b..f654d90 100644
--- a/src/gsm_data.c
+++ b/src/gsm_data.c
@@ -151,7 +151,7 @@
 char *gsm_ts_name(struct gsm_bts_trx_ts *ts)
 {
 	snprintf(ts2str, sizeof(ts2str), "(bts=%d,trx=%d,ts=%d)",
-		 ts->trx->bts->nr, ts->trx->nr, ts->nr);
+		 ts->trx->bts->bts_nr, ts->trx->nr, ts->nr);
 
 	return ts2str;
 }