serial: 8250_pnp: Move to struct dev_pm_ops

The established way to provide PM callbacks is through struct dev_pm_ops
which is more generic.

Convert driver to use it instead of legacy approach.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20190726172817.73253-1-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_pnp.c

@@ -498,10 +498,9 @@ static void serial_pnp_remove(struct pnp_dev *dev)
 		serial8250_unregister_port(line - 1);
 }
 
-#ifdef CONFIG_PM
-static int serial_pnp_suspend(struct pnp_dev *dev, pm_message_t state)
+static int __maybe_unused serial_pnp_suspend(struct device *dev)
 {
-	long line = (long)pnp_get_drvdata(dev);
+	long line = (long)dev_get_drvdata(dev);
 
 	if (!line)
 		return -ENODEV;
@@ -509,26 +508,25 @@ static int serial_pnp_suspend(struct pnp_dev *dev, pm_message_t state)
 	return 0;
 }
 
-static int serial_pnp_resume(struct pnp_dev *dev)
+static int __maybe_unused serial_pnp_resume(struct device *dev)
 {
-	long line = (long)pnp_get_drvdata(dev);
+	long line = (long)dev_get_drvdata(dev);
 
 	if (!line)
 		return -ENODEV;
 	serial8250_resume_port(line - 1);
 	return 0;
 }
-#else
-#define serial_pnp_suspend NULL
-#define serial_pnp_resume NULL
-#endif /* CONFIG_PM */
+
+static SIMPLE_DEV_PM_OPS(serial_pnp_pm_ops, serial_pnp_suspend, serial_pnp_resume);
 
 static struct pnp_driver serial_pnp_driver = {
 	.name		= "serial",
 	.probe		= serial_pnp_probe,
 	.remove		= serial_pnp_remove,
-	.suspend	= serial_pnp_suspend,
-	.resume		= serial_pnp_resume,
+	.driver         = {
+		.pm     = &serial_pnp_pm_ops,
+	},
 	.id_table	= pnp_dev_table,
 };