iio: at91_adc: Use devm_kcalloc to allocate arrays

Use dev_kcalloc instead of devm_kzalloc to allocate arrays since it is
semantically more appropriate.

While we are at it the patch also fixes the following coccinelle warning:
	drivers/iio/adc/at91_adc.c:277:25-31: ERROR: application of sizeof to pointer
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-By: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/adc/at91_adc.c

@@ -123,10 +123,8 @@ static int at91_adc_channel_init(struct iio_dev *idev)
 	idev->num_channels = bitmap_weight(&st->channels_mask,
 					   st->num_channels) + 1;
 
-	chan_array = devm_kzalloc(&idev->dev,
-				  ((idev->num_channels + 1) *
-					sizeof(struct iio_chan_spec)),
-				  GFP_KERNEL);
+	chan_array = devm_kcalloc(&idev->dev, idev->num_channels + 1,
+					sizeof(*chan_array), GFP_KERNEL);
 
 	if (!chan_array)
 		return -ENOMEM;
@@ -270,9 +268,8 @@ static int at91_adc_trigger_init(struct iio_dev *idev)
 	struct at91_adc_state *st = iio_priv(idev);
 	int i, ret;
 
-	st->trig = devm_kzalloc(&idev->dev,
-				st->trigger_number * sizeof(st->trig),
-				GFP_KERNEL);
+	st->trig = devm_kcalloc(&idev->dev, st->trigger_number,
+				sizeof(*st->trig), GFP_KERNEL);
 
 	if (st->trig == NULL) {
 		ret = -ENOMEM;
@@ -454,9 +451,8 @@ static int at91_adc_probe_dt(struct at91_adc_state *st,
 	st->registers->trigger_register = prop;
 
 	st->trigger_number = of_get_child_count(node);
-	st->trigger_list = devm_kzalloc(&idev->dev, st->trigger_number *
-					sizeof(struct at91_adc_trigger),
-					GFP_KERNEL);
+	st->trigger_list = devm_kcalloc(&idev->dev, st->trigger_number,
+					sizeof(*st->trigger_list), GFP_KERNEL);
 	if (!st->trigger_list) {
 		dev_err(&idev->dev, "Could not allocate trigger list memory.\n");
 		ret = -ENOMEM;