cuart: reset on poweroff

Those settings (ccid setparameters, and internal uart driving) shiuld be
reset upon powering off.

Change-Id: I20bb650d731d54f743d7031fe67916239233ecd3
diff --git a/sysmoOCTSIM/cuart_driver_asf4_usart_async.c b/sysmoOCTSIM/cuart_driver_asf4_usart_async.c
index 42c2110..7822c1b 100644
--- a/sysmoOCTSIM/cuart_driver_asf4_usart_async.c
+++ b/sysmoOCTSIM/cuart_driver_asf4_usart_async.c
@@ -481,6 +481,12 @@
 		settings.vsel = v;
 		ncn8025_set(cuart->u.asf4.slot_nr, &settings);
 
+		/* we have to reset this somewhere, and powering down loses all state */
+		if (!arg) {
+			cuart->tx_busy = false;
+			cuart->wtime_etu = 9600; /* ISO 7816-3 Section 8.1 */
+		}
+
 		break;
 	case CUART_CTL_WTIME:
 		/* no driver-specific handling of this */