staging: iio: adc: ad7280a: fix permission coding style issue

Symbolic permissions 'S_IWUSR | S_IRUGO' are not preferred. Consider using
octal permissions '0644'. Found running checkpatch.
Signed-off-by: Olivier Leveque <o_leveque@orange.fr>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/staging/iio/adc/ad7280a.c

@@ -560,7 +560,7 @@ static int ad7280_attr_init(struct ad7280_state *st)
 			st->iio_attr[cnt].address =
 				AD7280A_DEVADDR(dev) << 8 | ch;
 			st->iio_attr[cnt].dev_attr.attr.mode =
-				S_IWUSR | S_IRUGO;
+				0644;
 			st->iio_attr[cnt].dev_attr.show =
 				ad7280_show_balance_sw;
 			st->iio_attr[cnt].dev_attr.store =
@@ -577,7 +577,7 @@ static int ad7280_attr_init(struct ad7280_state *st)
 				AD7280A_DEVADDR(dev) << 8 |
 				(AD7280A_CB1_TIMER + ch);
 			st->iio_attr[cnt].dev_attr.attr.mode =
-				S_IWUSR | S_IRUGO;
+				0644;
 			st->iio_attr[cnt].dev_attr.show =
 				ad7280_show_balance_timer;
 			st->iio_attr[cnt].dev_attr.store =
@@ -746,26 +746,26 @@ static irqreturn_t ad7280_event_handler(int irq, void *private)
 
 static IIO_DEVICE_ATTR_NAMED(in_thresh_low_value,
 		in_voltage-voltage_thresh_low_value,
-		S_IRUGO | S_IWUSR,
+		0644,
 		ad7280_read_channel_config,
 		ad7280_write_channel_config,
 		AD7280A_CELL_UNDERVOLTAGE);
 
 static IIO_DEVICE_ATTR_NAMED(in_thresh_high_value,
 		in_voltage-voltage_thresh_high_value,
-		S_IRUGO | S_IWUSR,
+		0644,
 		ad7280_read_channel_config,
 		ad7280_write_channel_config,
 		AD7280A_CELL_OVERVOLTAGE);
 
 static IIO_DEVICE_ATTR(in_temp_thresh_low_value,
-		S_IRUGO | S_IWUSR,
+		0644,
 		ad7280_read_channel_config,
 		ad7280_write_channel_config,
 		AD7280A_AUX_ADC_UNDERVOLTAGE);
 
 static IIO_DEVICE_ATTR(in_temp_thresh_high_value,
-		S_IRUGO | S_IWUSR,
+		0644,
 		ad7280_read_channel_config,
 		ad7280_write_channel_config,
 		AD7280A_AUX_ADC_OVERVOLTAGE);