Use managed resource functions like devm_kasprintf and
devm_power_supply_register in bq24735_charger_probe. To be
compatible with the change, replace various gotos by direct
returns and drop unneeded labels.

Also, remove bq24735_charger_remove as it is now redundant.
Signed-off-by: Vaishali Thakkar <vthakkar1994@gmail.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>