serial: xuartps: Fix iobase use.

cdns_uart_get_port() sets port->iobase = 1 to "mark port in use", but
this "in use" condition is not checked anywhere else in the code. So
remove the line, keeping port->iobase = 0 (which also makes more sense).
Signed-off-by: Thomas Betker <thomas.betker@rohde-schwarz.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/xilinx_uartps.c

@@ -1038,7 +1038,6 @@ static struct uart_port *cdns_uart_get_port(int id)
 	/* At this point, we've got an empty uart_port struct, initialize it */
 	spin_lock_init(&port->lock);
 	port->membase	= NULL;
-	port->iobase	= 1; /* mark port in use */
 	port->irq	= 0;
 	port->type	= PORT_UNKNOWN;
 	port->iotype	= UPIO_MEM32;