regulator: Remove all platform_set_drvdata(pdev, NULL) in drivers

Since 0998d06310 "device-core: Ensure drvdata = NULL when no driver is bound",
this is done by driver core after device_release or on probe failure.
Thus we can remove all platform_set_drvdata(pdev, NULL) in drivers.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/regulator/wm8400-regulator.c

@@ -250,7 +250,6 @@ static int wm8400_regulator_remove(struct platform_device *pdev)
 {
 	struct regulator_dev *rdev = platform_get_drvdata(pdev);
 
-	platform_set_drvdata(pdev, NULL);
 	regulator_unregister(rdev);
 
 	return 0;