8250_men_mcb: Fix unsigned comparison with less than zero

The data->line[i] is defined as unsigned int type, if(data->line[i] < 0)
is invalid, so replace data->line[i] with res.

./drivers/tty/serial/8250/8250_men_mcb.c:223:6-19: WARNING: Unsigned expression compared with zero: data->line[i] < 0.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=6088


Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230803084753.51253-1-jiapeng.chong@linux.alibaba.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>