rx51_battery: Remove unnecessary platform_set_drvdata()

The driver core clears the driver data to NULL after device_release or on
probe failure, since commit 0998d0631001288a5974afc0b2a5f568bcdecb4d
(device-core: Ensure drvdata = NULL when no driver is bound). Thus, it is
not needed to manually clear the device driver data to NULL.

Signed-off-by: Jingoo Han <[e-mail]>
Signed-off-by: Anton Vorontsov <[e-mail]>

drivers/power/rx51_battery.c

···
 	di->bat.get_property = rx51_battery_get_property;
 
 	ret = power_supply_register(di->dev, &di->bat);
-	if (ret) {
-		platform_set_drvdata(pdev, NULL);
+	if (ret)
 		return ret;
-	}
 
 	return 0;
 }
···
 	struct rx51_device_info *di = platform_get_drvdata(pdev);
 
 	power_supply_unregister(&di->bat);
-	platform_set_drvdata(pdev, NULL);
 
 	return 0;
 }