bts-trx: Fix assert hit when rf_locked in .cfg and TS TCH/F_PDCH

If TRX is administratively locked during startup, for TS conigured as
TCH/F_PDCH the BSC will send a ACT PDCH message, but osmo-bts-trx won't
apply it by signalling it as available to the PCU, since the TRX is
locked.
That means the ts->flags contains the pending action to activate
it until it is unlocked. As a result, calling trx_set_ts() on it was
hitting the assert inside which expects not to apply the TS until it has
been confirmed by the PCU.
Let's still skip setting the TS and let pcu_tx_info_ind() trigger the
activation confirmation from PCU, since the TRX has just been unlocked.

Fixes following assert:
Assert failed (ts->flags & TS_F_PDCH_PENDING_MASK) == 0 /osmo-bts/src/osmo-bts-trx/l1_if.c:34

Change-Id: Ie3cad15d31870346d03a6e2f6dd32a9d2dd3067e

src/osmo-bts-trx/l1_if.c

@@ -702,6 +702,13 @@ int bts_model_chg_adm_state(struct gsm_bts *bts, struct gsm_abis_mo *mo,
 					 * internally restore the old status here.
 					 */
 					ts->dyn.pchan_is = ts->dyn.pchan_want;
+				} else if (ts->pchan == GSM_PCHAN_TCH_F_PDCH && ts->flags & TS_F_PDCH_PENDING_MASK) {
+					/* TS configuration already in progress,
+					 * waiting for PCU response, let it be
+					 * de/activated later by PCU ACT CNF as a
+					 * response to pcu_tx_info_ind()
+					 */
+					continue;
 				}
 				trx_set_ts(ts);
 			}