iio: Drop scan_type from viperboard adc driver

the driver does not support buffering, hence scan_type is not needed
Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Cc: Lars Poeschel <poeschel@lemonage.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/adc/viperboard_adc.c

@@ -42,12 +42,6 @@ struct vprbrd_adc {
 	.indexed = 1,					\
 	.channel = _index,				\
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
-	.scan_index = _index,				\
-	.scan_type = {					\
-		.sign = 'u',				\
-		.realbits = 8,				\
-		.storagebits = 8,			\
-	},						\
 }
 
 static struct iio_chan_spec const vprbrd_adc_iio_channels[] = {
@@ -73,7 +67,7 @@ static int vprbrd_iio_read_raw(struct iio_dev *iio_dev,
 		mutex_lock(&vb->lock);
 
 		admsg->cmd = VPRBRD_ADC_CMD_GET;
-		admsg->chan = chan->scan_index;
+		admsg->chan = chan->channel;
 		admsg->val = 0x00;
 
 		ret = usb_control_msg(vb->usb_dev,