regulator: max1586: add device-tree support

Add device-tree support to max1586.
The driver can still be used with the legacy platform data, or the new
device-tree way.

This work is heavily inspired by the device-tree support of its cousin
max8660 driver.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/include/linux/regulator/max1586.h b/include/linux/regulator/max1586.h
index de9a7fa..cedd0fe 100644
--- a/include/linux/regulator/max1586.h
+++ b/include/linux/regulator/max1586.h
@@ -40,7 +40,7 @@
  */
 struct max1586_subdev_data {
 	int				id;
-	char				*name;
+	const char			*name;
 	struct regulator_init_data	*platform_data;
 };