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>
diff --git a/drivers/acpi/acpica/evgpe.c b/drivers/acpi/acpica/evgpe.c
index deb26f4..57eeb3b 100644
--- a/drivers/acpi/acpica/evgpe.c
+++ b/drivers/acpi/acpica/evgpe.c
@@ -69,7 +69,7 @@
 acpi_ev_update_gpe_enable_masks(struct acpi_gpe_event_info *gpe_event_info)
 {
 	struct acpi_gpe_register_info *gpe_register_info;
-	u8 register_bit;
+	u32 register_bit;
 
 	ACPI_FUNCTION_TRACE(ev_update_gpe_enable_masks);
 
@@ -78,9 +78,8 @@
 		return_ACPI_STATUS(AE_NOT_EXIST);
 	}
 
-	register_bit = (u8)
-	    (1 <<
-	     (gpe_event_info->gpe_number - gpe_register_info->base_gpe_number));
+	register_bit = acpi_hw_gpe_register_bit(gpe_event_info,
+						gpe_register_info);
 
 	/* Clear the wake/run bits up front */