ACPICA: Store GPE register enable masks upfront

It is reported that ACPI interrupts do not work any more on
Dell Latitude D600 after commit c50f13c6 (ACPICA: Save
current masks of enabled GPEs after enable register writes).
The problem turns out to be related to the fact that the
enable_mask and enable_for_run GPE bit masks are not in
sync (in the absence of any system suspend/resume events)
for at least one GPE register on that machine.

Address this problem by writing the enable_for_run mask into
enable_mask as soon as enable_for_run is updated instead of
doing that only after the subsequent register write has
succeeded.  For consistency, update acpi_hw_gpe_enable_write()
to store the bit mask to be written into the GPE register
in enable_mask unconditionally before the write.

Since the ACPI_GPE_SAVE_MASK flag is not necessary any more after
that, drop it along with the symbols depending on it.

Reported-and-tested-by: Jim Bos <jim876@xs4all.nl>
Fixes: c50f13c6 (ACPICA: Save current masks of enabled GPEs after enable register writes)
Cc: 3.19+ <stable@vger.kernel.org> # 3.19+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>