tty: Return bool from tty_termios_hw_change()

Change tty_termios_hw_change() to return bool.

Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230117090358.4796-11-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>