88pm860x_battery: Convert to using managed resources
Use managed resource functions devm_request_threaded_irq and
devm_power_supply_register to simplify error handling.
To be compatible with the change, various gotos are replaced
with direct returns and unneeded labels are dropped. Also,
remove pm860x_battery_remove as it is now redundant.
Signed-off-by: Vaishali Thakkar <vthakkar1994@gmail.com> Signed-off-by: Sebastian Reichel <sre@kernel.org>