ACPI: resolve HP nx6125 S3 immediate wakeup regression

Moving disable GPEs from enter_sleep up into sleep_prepare fixed
the disabled SCI on S4 on Acer laptops.

However, it caused an immediate S3 resume on the HP nx6125.
Apparently, on the HP, a GPE was getting re-enabled after
the prepare, but before the enter.

Close that window by restoring the GPE disable on enter.
This is redundant in most cases, but closes this window,
where S3 and S4 paths differ.

Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Acked-by: Ray Lee <ray-lk@madrabbit.org>