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>

drivers/acpi/acpica/achware.h

@@ -90,6 +90,9 @@ acpi_status acpi_hw_write_port(acpi_io_address address, u32 value, u32 width);
 /*
  * hwgpe - GPE support
  */
+u32 acpi_hw_gpe_register_bit(struct acpi_gpe_event_info *gpe_event_info,
+			     struct acpi_gpe_register_info *gpe_register_info);
+
 acpi_status acpi_hw_low_disable_gpe(struct acpi_gpe_event_info *gpe_event_info);
 
 acpi_status