[vty] Add option to disable RF on a given TRX.

- Make sure that on runtime the Radio Carrier can be
  locked and unlocked. The vty code calls into the
  Abis NM to lock/unlock the channel and the state is
  stored there.

- Make sure that on start the Radio Carries remains
  offline and we are not starting it. On start the
  radio carrier is either locked or unlocked. This means
  the RSL will not connect until the RF is unlocked. It
  will connect then. To see RSL bringup failures one
  needs to parse the RSL nack message.

- When the TRX is locked on startup the RSL link will
  only be established after it will be unlocked.
diff --git a/openbsc/src/vty_interface.c b/openbsc/src/vty_interface.c
index f8bba2c..066dfd5 100644
--- a/openbsc/src/vty_interface.c
+++ b/openbsc/src/vty_interface.c
@@ -1200,6 +1200,17 @@
 	return CMD_SUCCESS;
 }
 
+DEFUN(cfg_trx_rf_locked,
+      cfg_trx_rf_locked_cmd,
+      "rf_locked (0|1)",
+      "Turn off RF of the TRX.\n")
+{
+	int locked = atoi(argv[0]);
+	struct gsm_bts_trx *trx = vty->index;
+
+	gsm_trx_lock_rf(trx, locked);
+	return CMD_SUCCESS;
+}
 
 /* per TS configuration */
 DEFUN(cfg_ts,
@@ -1321,6 +1332,7 @@
 	install_element(TRX_NODE, &cfg_trx_max_power_red_cmd);
 	install_element(TRX_NODE, &cfg_trx_rsl_e1_cmd);
 	install_element(TRX_NODE, &cfg_trx_rsl_e1_tei_cmd);
+	install_element(TRX_NODE, &cfg_trx_rf_locked_cmd);
 
 	install_element(TRX_NODE, &cfg_ts_cmd);
 	install_node(&ts_node, dummy_config_write);