ACPICA: Events: Fix edge-triggered GPE by disabling before acknowledging it.

Due to ACPI specificiation 5, chapter 5.6.4 General-Purpose Event Handling,
OSPMs need to disable GPE before clearing the status bit for edge-triggered
GPEs.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Tested-by: Gareth Williams <gareth@garethwilliams.me.uk>
Tested-by: Steffen Weber <steffen.weber@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>