PM / sleep: convert to DEFINE_SHOW_ATTRIBUTE

Use DEFINE_SHOW_ATTRIBUTE macro to simplify the code.
Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

kernel/power/main.c

@@ -318,23 +318,12 @@ static int suspend_stats_show(struct seq_file *s, void *unused)
 
 	return 0;
 }
-
-static int suspend_stats_open(struct inode *inode, struct file *file)
-{
-	return single_open(file, suspend_stats_show, NULL);
-}
-
-static const struct file_operations suspend_stats_operations = {
-	.open           = suspend_stats_open,
-	.read           = seq_read,
-	.llseek         = seq_lseek,
-	.release        = single_release,
-};
+DEFINE_SHOW_ATTRIBUTE(suspend_stats);
 
 static int __init pm_debugfs_init(void)
 {
 	debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
-			NULL, NULL, &suspend_stats_operations);
+			NULL, NULL, &suspend_stats_fops);
 	return 0;
 }