serial: Make uart_handle_cts_change() status param bool active

Convert uart_handle_cts_change() to bool which is more appropriate
than unsigned int.

Rename status to active to better describe what the parameter means.
While at it, make the comment about the active parameter easier to
parse.

Cleanup callsites from operations that are not necessary with bool.

Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230117090358.4796-10-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>