plat-nomadik: make GPIO interrupts work with cpuidle ApSleep

Enable wakeups by default for any GPIO interrupts and in the suspend/resume
path narrow this down to only the the real wakeup interrupts. This approach is
based on the assumption that cpuidle ApSleep will be entered more often than
system suspend.

Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Reviewed-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
[Fixup for genirq changes to struct irq_data on 2.6.38]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>