Input: gpio_keys: report a wakeup_event for a button press on a wake_up button.

In order to avoid races with suspend, a wakeup event must register as
such by calling pm_wakeup_event() or pm_stay_awake.  This will ensure
that the current suspend cycle aborts.

When the user-space visible event is created in the interrupt handled
(gpio_keys_irq_isr), and simple pm_wakeup_event() with no delay is
sufficient as suspend will synchronise with all interrupt delivery.

When the user-space visible event is create later
(gpio_keys_gpio_isr), we need to bracket the event with
pm_stay_awake() and pm_relax().

Signed-off-by: NeilBrown <neilb@suse.de>
Conflicts:

	drivers/input/keyboard/gpio_keys.c