staging: comedi: amplc_pci224: sample types are unsigned

Sample values in comedi are generally represented as unsigned values.
Change the type of the `ao_scan_vals` member of `struct pci224_private`
from `short *` to `unsigned short *` for consistency.  Also change the
type of the `array` variable in `pci224_ao_munge()` from `short *` to
`unsigned short *`.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/amplc_pci224.c

@@ -373,7 +373,7 @@ struct pci224_private {
 	unsigned long state;
 	spinlock_t ao_spinlock;
 	unsigned int *ao_readback;
-	short *ao_scan_vals;
+	unsigned short *ao_scan_vals;
 	unsigned char *ao_scan_order;
 	int intr_cpuid;
 	short intr_running;
@@ -1112,7 +1112,7 @@ pci224_ao_munge(struct comedi_device *dev, struct comedi_subdevice *s,
 	const struct pci224_board *thisboard = comedi_board(dev);
 	struct pci224_private *devpriv = dev->private;
 	struct comedi_async *async = s->async;
-	short *array = data;
+	unsigned short *array = data;
 	unsigned int length = num_bytes / sizeof(*array);
 	unsigned int offset;
 	unsigned int shift;