staging: comedi: add an 'mmio' member to comedi_device

All the comedi drivers that use memory mapped io currently have a
void __iomem * member in their private data for the driver. For
some of the drivers this is actually the only member in that data.

For convienence, add a new member to the comedi_device for this
void __iomem *.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/comedidev.h

@@ -253,6 +253,7 @@ struct comedi_device {
 	struct comedi_subdevice *subdevices;
 
 	/* dumb */
+	void __iomem *mmio;
 	unsigned long iobase;
 	unsigned long iolen;
 	unsigned int irq;

drivers/staging/comedi/drivers.c

@@ -121,6 +121,7 @@ static void comedi_device_detach_cleanup(struct comedi_device *dev)
 	dev->driver = NULL;
 	dev->board_name = NULL;
 	dev->board_ptr = NULL;
+	dev->mmio = NULL;
 	dev->iobase = 0;
 	dev->iolen = 0;
 	dev->ioenabled = false;