mtd: mtdpart: use DEVICE_ATTR_RO() helper macro

Use DEVICE_ATTR_RO() helper macro instead of plain DEVICE_ATTR(), which
makes the code a bit shorter and easier to read.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210603123041.12036-1-thunder.leizhen@huawei.com

drivers/mtd/mtdpart.c

@@ -212,15 +212,14 @@ static struct mtd_info *allocate_partition(struct mtd_info *parent,
 	return child;
 }
 
-static ssize_t mtd_partition_offset_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
+static ssize_t offset_show(struct device *dev,
+			   struct device_attribute *attr, char *buf)
 {
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 
 	return sysfs_emit(buf, "%lld\n", mtd->part.offset);
 }
-
-static DEVICE_ATTR(offset, S_IRUGO, mtd_partition_offset_show, NULL);
+static DEVICE_ATTR_RO(offset);	/* mtd partition offset */
 
 static const struct attribute *mtd_partition_attrs[] = {
 	&dev_attr_offset.attr,