memory tier: use helper macro __ATTR_RW()

Use helper macro __ATTR_RW to define numa demotion attributes.  Minor
readability improvement.

Link: https://lkml.kernel.org/r/20230715035111.2656784-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/memory-tiers.c

@@ -672,16 +672,16 @@ bool numa_demotion_enabled = false;
 
 #ifdef CONFIG_MIGRATION
 #ifdef CONFIG_SYSFS
-static ssize_t numa_demotion_enabled_show(struct kobject *kobj,
-					  struct kobj_attribute *attr, char *buf)
+static ssize_t demotion_enabled_show(struct kobject *kobj,
+				     struct kobj_attribute *attr, char *buf)
 {
 	return sysfs_emit(buf, "%s\n",
 			  numa_demotion_enabled ? "true" : "false");
 }
 
-static ssize_t numa_demotion_enabled_store(struct kobject *kobj,
-					   struct kobj_attribute *attr,
-					   const char *buf, size_t count)
+static ssize_t demotion_enabled_store(struct kobject *kobj,
+				      struct kobj_attribute *attr,
+				      const char *buf, size_t count)
 {
 	ssize_t ret;
 
@@ -693,8 +693,7 @@ static ssize_t numa_demotion_enabled_store(struct kobject *kobj,
 }
 
 static struct kobj_attribute numa_demotion_enabled_attr =
-	__ATTR(demotion_enabled, 0644, numa_demotion_enabled_show,
-	       numa_demotion_enabled_store);
+	__ATTR_RW(demotion_enabled);
 
 static struct attribute *numa_attrs[] = {
 	&numa_demotion_enabled_attr.attr,