serdev: ttyport: release tty lock sooner on open

Release the tty lock once tty-driver open returns to make it clear that
it does not protect neither tty->termios or the serport flags.
Signed-off-by: NJohan Hovold <johan@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serdev/serdev-ttyport.c

@@ -104,6 +104,8 @@ static int ttyport_open(struct serdev_controller *ctrl)
 	if (ret)
 		goto err_close;
 
+	tty_unlock(serport->tty);
+
 	/* Bring the UART into a known 8 bits no parity hw fc state */
 	ktermios = tty->termios;
 	ktermios.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP |
@@ -117,7 +119,6 @@ static int ttyport_open(struct serdev_controller *ctrl)
 
 	set_bit(SERPORT_ACTIVE, &serport->flags);
 
-	tty_unlock(serport->tty);
 	return 0;
 
 err_close: