leds: wm831x-status: Use devm_led_classdev_register
Switch to resource-managed function devm_led_classdev_register instead
of led_classdev_register and remove unneeded led_classdev_unregister.
Also, remove platform_set_drvdata from probe function and the remove
function, wm831x_status_remove as it is now has nothing to do.
The Coccinelle semantic patch used to make this change is as follows:
//<smpl>
@platform@
identifier p, probefn, removefn;
@@
struct platform_driver p = {
.probe = probefn,
.remove = removefn,
};