iio: adc: at91_adc: simplify timestamp channel definition

Use IIO_CHAN_SOFT_TIMESTAMP() to define the timestamp channel instead of
manually filling in the struct iio_chan_spec fields. This makes the code
less verbose and mistake-prone.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Author: dlech

drivers/iio/adc/at91_adc.c

@@ -481,7 +481,7 @@ static irqreturn_t at91_adc_9x5_interrupt(int irq, void *private)
 static int at91_adc_channel_init(struct iio_dev *idev)
 {
 	struct at91_adc_state *st = iio_priv(idev);
-	struct iio_chan_spec *chan_array, *timestamp;
+	struct iio_chan_spec *chan_array;
 	int bit, idx = 0;
 	unsigned long rsvd_mask = 0;
 
@@ -519,14 +519,8 @@ static int at91_adc_channel_init(struct iio_dev *idev)
 		chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
 		idx++;
 	}
-	timestamp = chan_array + idx;
-
-	timestamp->type = IIO_TIMESTAMP;
-	timestamp->channel = -1;
-	timestamp->scan_index = idx;
-	timestamp->scan_type.sign = 's';
-	timestamp->scan_type.realbits = 64;
-	timestamp->scan_type.storagebits = 64;
+
+	chan_array[idx] = IIO_CHAN_SOFT_TIMESTAMP(idx);
 
 	idev->channels = chan_array;
 	return idev->num_channels;