make sure all channels in one BTS use the same TSC (training sequence code)

diff --git a/src/gsm_data.c b/src/gsm_data.c
index d0ce168..e6447d9 100644
--- a/src/gsm_data.c
+++ b/src/gsm_data.c
@@ -108,6 +108,7 @@
 		bts->network = net;
 		bts->nr = i;
 		bts->type = bts_type;
+		bts->tsc = HARDCODED_TSC;
 
 		for (j = 0; j < BTS_MAX_TRX; j++) {
 			struct gsm_bts_trx *trx = &bts->trx[j];