power: gpio-charger: balance enable/disable_irq_wake calls

enable_irq_wakeup returns 0 in case it correctly enabled the IRQ to
generate the wakeup event (and thus resume should call disable_irq_wake).
Currently gpio-charger driver has this logic inverted. Correct that thus
correcting enable/disable_irq_wake() calls balance.

Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>