serial: 8250_fintek: Disable delays for ports != 0

According to the datasheet, only the first port supports delay before
send and delay after send.

Reported-by: "Ji-Ze Hong (Peter Hong)" <hpeter@gmail.com>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>