abis_om2k: fix typo that declared non-existent struct gsm_bts_trx_s

The typo was recently committed in 80ccb952676cb4a068410991c5d53d19f228f695,
"OM2000: Fix missing dynamic TCH initialization"

Change-Id: I8e3eec8cf63494962fa31d85a0ec9db9a9e5df46
diff --git a/openbsc/src/libbsc/abis_om2000.c b/openbsc/src/libbsc/abis_om2000.c
index 0dffb15..6b334d4 100644
--- a/openbsc/src/libbsc/abis_om2000.c
+++ b/openbsc/src/libbsc/abis_om2000.c
@@ -1682,7 +1682,7 @@
 	/* if we have just received opinfo accept for the timeslot,
 	 * start dynamic TCH switching procedures */
 	if (omfp->mo->addr.class == OM2K_MO_CLS_TS) {
-		struct gsm_bts_trx_s *ts;
+		struct gsm_bts_trx_ts *ts;
 		ts = mo2obj(omfp->trx->bts, &omfp->mo->addr);
 		dyn_ts_init(ts);
 	}