Since acpi_hw_enable_wakeup_gpe_block() is currently always called
after disabling all GPEs, it can actually write zeros to all
non-wakeup enable bits unconditionally.

That will be useful going forward for disabling runtime GPEs and
enabling wakeup GPEs in one go instead of doing that in two steps
(disable runtime and enable wakeup) which in theory may lead to a
loss of a wakeup event.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>