tty: serial: samsung: change has_divslot type to bool

tty: serial: samsung: change has_divslot type to bool

Since the driver was introduced the port features flags never extended.
As we don't expect more flags soon that would bypass the first
cacheline of ``struct s3c24xx_uart_info``, change the type of
``has_divslot`` to bool. Bitfields operations incur performance penalty
when set or read as compared to direct types.

Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Link: https://lore.kernel.org/r/20240119104526.1221243-19-tudor.ambarus@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>