staging: comedi: icp_multi: sample types are unsigned

Sample values in comedi are generally represented as unsigned values.
Change the element type of the `ao_data[]` member of `struct
icp_multi_private` from `short` to `unsigned short` for consistency.

Also remove the `ai_data` and `di_data` members as they are not used.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/icp_multi.c

@@ -118,9 +118,7 @@ struct icp_multi_private {
 	unsigned char act_chanlist_len;	/*  len of scanlist */
 	unsigned char act_chanlist_pos;	/*  actual position in MUX list */
 	unsigned int *ai_chanlist;	/*  actaul chanlist */
-	short *ai_data;		/*  data buffer */
-	short ao_data[4];	/*  data output buffer */
-	short di_data;		/*  Digital input data */
+	unsigned short ao_data[4];	/*  data output buffer */
 	unsigned int do_data;	/*  Remember digital output data */
 };