complete ->[sg]et_serial() switchover

Reviewed-by: Johan Hovold <[e-mail]>
Signed-off-by: Al Viro <[e-mail]>

drivers/tty/tty_io.c

···
 		pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
 			__func__, get_task_comm(comm, current), flags);
 	if (!tty->ops->set_serial)
-		return -ENOIOCTLCMD;
+		return -ENOTTY;
 	return tty->ops->set_serial(tty, &v);
 }
 
···
 
 	memset(&v, 0, sizeof(struct serial_struct));
 	if (!tty->ops->get_serial)
-		return -ENOIOCTLCMD;
+		return -ENOTTY;
 	err = tty->ops->get_serial(tty, &v);
 	if (!err && copy_to_user(ss, &v, sizeof(struct serial_struct)))
 		err = -EFAULT;
···
 		}
 		break;
 	case TIOCSSERIAL:
-		retval = tty_tiocsserial(tty, p);
-		if (retval != -ENOIOCTLCMD)
-			return retval;
-		break;
+		return tty_tiocsserial(tty, p);
 	case TIOCGSERIAL:
-		retval = tty_tiocgserial(tty, p);
-		if (retval != -ENOIOCTLCMD)
-			return retval;
-		break;
+		return tty_tiocgserial(tty, p);
 	case TIOCGPTPEER:
 		/* Special because the struct file is needed */
 		return ptm_open_peer(file, tty, (int)arg);

drivers/usb/serial/usb-serial.c

···
 
 	if (port->serial->type->get_serial)
 		return port->serial->type->get_serial(tty, ss);
-	return -ENOIOCTLCMD;
+	return -ENOTTY;
 }
 
 static int serial_set_serial(struct tty_struct *tty, struct serial_struct *ss)
···
 
 	if (port->serial->type->set_serial)
 		return port->serial->type->set_serial(tty, ss);
-	return -ENOIOCTLCMD;
+	return -ENOTTY;
 }
 
 static int serial_ioctl(struct tty_struct *tty,