iio: adc: ad4030: replace sprintf() with sysfs_emit()

Update the ad4030_read_label() function to use sysfs_emit() for generating
labels.

Signed-off-by: Nuno Sá <[e-mail]>
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/adc/ad4030.c

···
 			     char *label)
 {
 	if (chan->differential)
-		return sprintf(label, "differential%lu\n", chan->address);
-	return sprintf(label, "common-mode%lu\n", chan->address);
+		return sysfs_emit(label, "differential%lu\n", chan->address);
+	return sysfs_emit(label, "common-mode%lu\n", chan->address);
 }
 
 static int ad4030_get_current_scan_type(const struct iio_dev *indio_dev,