ACPI: enable ACPI SCI during suspend

Enable ACPI SCI during suspend so that SCI can be used
as wake events for PM_SUSPEND_FREEZE.

For S3/S4 transition,
We disable all GPEs in suspend_ops->prepare_late() to
fix a problem that GPEs may trigger SCI  before
arch_suspend_disable_irqs() is run.
So it is safe to leave the SCI enabled until
arch_suspend_irq_disable() is run.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>