ACPICA: Misc comments to minimize code divergence

Modify/add some comments to minimize ACPICA/linux GPE code divergence.

Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/acpica/achware.h b/drivers/acpi/acpica/achware.h
index 167470a..258d628 100644
--- a/drivers/acpi/acpica/achware.h
+++ b/drivers/acpi/acpica/achware.h
@@ -94,7 +94,7 @@
 			     struct acpi_gpe_register_info *gpe_register_info);
 
 acpi_status
-acpi_hw_low_set_gpe(struct acpi_gpe_event_info *gpe_event_info, u8 action);
+acpi_hw_low_set_gpe(struct acpi_gpe_event_info *gpe_event_info, u32 action);
 
 acpi_status
 acpi_hw_disable_gpe_block(struct acpi_gpe_xrupt_info *gpe_xrupt_info,