mtd: Switch to PM ops

Use dev_pm_ops instead of the legacy suspend/resume callbacks for the MTD
class suspend and resume operations.

While we are at it slightly reorder things to avoid the need for forward
declarations.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/mtdcore.c

@@ -48,14 +48,34 @@
 static struct backing_dev_info mtd_bdi = {
 };
 
-static int mtd_cls_suspend(struct device *dev, pm_message_t state);
-static int mtd_cls_resume(struct device *dev);
+#ifdef CONFIG_PM_SLEEP
+
+static int mtd_cls_suspend(struct device *dev)
+{
+	struct mtd_info *mtd = dev_get_drvdata(dev);
+
+	return mtd ? mtd_suspend(mtd) : 0;
+}
+
+static int mtd_cls_resume(struct device *dev)
+{
+	struct mtd_info *mtd = dev_get_drvdata(dev);
+
+	if (mtd)
+		mtd_resume(mtd);
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(mtd_cls_pm_ops, mtd_cls_suspend, mtd_cls_resume);
+#define MTD_CLS_PM_OPS (&mtd_cls_pm_ops)
+#else
+#define MTD_CLS_PM_OPS NULL
+#endif
 
 static struct class mtd_class = {
 	.name = "mtd",
 	.owner = THIS_MODULE,
-	.suspend = mtd_cls_suspend,
-	.resume = mtd_cls_resume,
+	.pm = MTD_CLS_PM_OPS,
 };
 
 static DEFINE_IDR(mtd_idr);
@@ -88,22 +108,6 @@ static void mtd_release(struct device *dev)
 	device_destroy(&mtd_class, index + 1);
 }
 
-static int mtd_cls_suspend(struct device *dev, pm_message_t state)
-{
-	struct mtd_info *mtd = dev_get_drvdata(dev);
-
-	return mtd ? mtd_suspend(mtd) : 0;
-}
-
-static int mtd_cls_resume(struct device *dev)
-{
-	struct mtd_info *mtd = dev_get_drvdata(dev);
-
-	if (mtd)
-		mtd_resume(mtd);
-	return 0;
-}
-
 static ssize_t mtd_type_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {