mtd: core: add MTD_DEVICE_ATTR_RO/RW() helper macros

Compared with the definition of DEVICE_ATTR_RO/RW(), the read and write
function names of the sysfs attribute have an additional "mtd_" prefix.
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/20210603125323.12142-2-thunder.leizhen@huawei.com

drivers/mtd/mtdcore.c

@@ -96,6 +96,12 @@ static void mtd_release(struct device *dev)
 	device_destroy(&mtd_class, index + 1);
 }
 
+#define MTD_DEVICE_ATTR_RO(name) \
+static DEVICE_ATTR(name, 0444, mtd_##name##_show, NULL)
+
+#define MTD_DEVICE_ATTR_RW(name) \
+static DEVICE_ATTR(name, 0644, mtd_##name##_show, mtd_##name##_store)
+
 static ssize_t mtd_type_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {