staging: comedi: ii_pci20kc: use comedi_alloc_spriv()

For aesthetic reasons, use the helper function to allocate the
subdevice private data instead of hanging it on the device
private data. The core will free the memory during the detach.
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/ii_pci20kc.c

@@ -149,9 +149,7 @@ union pci20xxx_subdev_private {
 };
 
 struct pci20xxx_private {
-
 	void __iomem *ioaddr;
-	union pci20xxx_subdev_private subdev_private[PCI20000_MODULES];
 };
 
 #define CHAN (CR_CHAN(it->chanlist[0]))
@@ -222,9 +220,10 @@ static int pci20xxx_attach(struct comedi_device *dev,
 
 	for (i = 0; i < PCI20000_MODULES; i++) {
 		s = &dev->subdevices[i];
+		sdp = comedi_alloc_spriv(s, sizeof(*sdp));
+		if (!sdp)
+			return -ENOMEM;
 		id = readb(devpriv->ioaddr + (i + 1) * PCI20000_OFFSET);
-		s->private = devpriv->subdev_private + i;
-		sdp = s->private;
 		switch (id) {
 		case PCI20006_ID:
 			sdp->pci20006.iobase =