power: supply: ab8500_fg: Do not free non-requested IRQs in probe's error path

When requesting interrupt fails, free only interrupts already requested,
not all of them.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>