drivers/video/backlight/wm831x_bl.c: use devm_ functions

The various devm_ functions allocate memory that is released when a driver
detaches.  This patch uses these functions for data that is allocated in
the probe function of a platform device and is only freed in the remove
function.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/backlight/wm831x_bl.c

@@ -186,7 +186,7 @@ static int wm831x_backlight_probe(struct platform_device *pdev)
 	if (ret < 0)
 		return ret;
 
-	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 	if (data == NULL)
 		return -ENOMEM;
 
@@ -200,7 +200,6 @@ static int wm831x_backlight_probe(struct platform_device *pdev)
 				       &wm831x_backlight_ops, &props);
 	if (IS_ERR(bl)) {
 		dev_err(&pdev->dev, "failed to register backlight\n");
-		kfree(data);
 		return PTR_ERR(bl);
 	}
 
@@ -211,7 +210,6 @@ static int wm831x_backlight_probe(struct platform_device *pdev)
 	/* Disable the DCDC if it was started so we can bootstrap */
 	wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0);
 
-
 	backlight_update_status(bl);
 
 	return 0;
@@ -220,10 +218,8 @@ static int wm831x_backlight_probe(struct platform_device *pdev)
 static int wm831x_backlight_remove(struct platform_device *pdev)
 {
 	struct backlight_device *bl = platform_get_drvdata(pdev);
-	struct wm831x_backlight_data *data = bl_get_data(bl);
 
 	backlight_device_unregister(bl);
-	kfree(data);
 	return 0;
 }