serial: sh-sci: Set the UPF_FIXED_PORT flag

The base address, IRQ and baud rate generator parent clock rate can't be
changed by userspace. Mark the port as fixed.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

drivers/tty/serial/sh-sci.c

@@ -2248,7 +2248,7 @@ static int sci_init_single(struct platform_device *dev,
 
 	port->mapbase		= p->mapbase;
 	port->type		= p->type;
-	port->flags		= p->flags;
+	port->flags		= UPF_FIXED_PORT | p->flags;
 	port->regshift		= p->regshift;
 
 	/*