ACPI / ACPICA: Use helper function for computing GPE masks
In quite a few places ACPICA needs to compute a GPE enable mask with
only one bit, corresponding to a given GPE, set. Currently, that
computation is always open coded which leads to unnecessary code
duplication. Fix this by introducing a helper function for computing
one-bit GPE enable masks and using it where appropriate.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>