power: supply: ab8500: Clean some error messages

There is an useless extra comma at the end of some error messages, remove
them.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/e7ac0fa83c6100cbe4e0efa90cf99291c2423b10.1719037737.git.christophe.jaillet@wanadoo.fr


Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>