serial8250_register_port — register a serial port
int serial8250_register_port (struct uart_port * port);
Configure the serial port specified by the request. If the port exists and is in use, it is hung up and unregistered first.
The port is then probed and if necessary the IRQ is autodetected If this fails an error is returned.
On success the port is ready to use and the line number is returned.