gpio_keys: Remove triplicate reporting of wakeups

Wake keys were being triggered 3 times on wake, causing a
ON/OFF/ON sequence: The key itself, once when disabling irqwake,
and then once more as a gpio event. If one of the events
was lost for some reason (like debouncing pauses), we'd
end up with "ON/OFF", and the device wouldn't actually turn
on.
Get rid of the 2 superfluous reports.

Origin: https://github.com/CyanogenMod/lge-kernel-p880/commit/c440e1fa57ab7b05016f97cbac8db5013ddfe4a1

Author: cyanogenmod@cerqueira.org