ARM: exynos4/5: convert pmu wakeup to stacked domains

Exynos has been (ab)using the gic_arch_extn to provide
wakeup from suspend, and it makes a lot of sense to convert
this code to use stacked domains instead.

This patch does just this, updating the DT files to actually
reflect what the HW provides.

BIG FAT WARNING: because the DTs were so far lying by not
exposing the fact that the PMU block is actually the first
interrupt controller in the chain for RTC, kernels with this patch
applied wont have any suspend-resume facility when booted
with old DTs, and old kernels with updated DTs may not even boot.

Also, I strongly suspect that there is more than two wake-up
interrupts on these platforms, but I leave it to the maintainers
to fix their mess.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Link: https://lkml.kernel.org/r/1426088693-15724-2-git-send-email-marc.zyngier@arm.com
[ jac: squash in maz's fixup from
  https://lkml.kernel.org/r/5506989D.9050703@arm.com

 ]
Signed-off-by: Jason Cooper <jason@lakedaemon.net>