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.

Change-Id: Ic49fbe8d0cdaa8138ace069b784a68b5ad6f7afc