ACPICA: Events: Add support to return both enable/status register values for GPE and fixed event.

ACPICA commit e25d791e4b3d5b9f4ead298269610cb05f89749a

There is a facility in Linux, developers can obtain GPE and fixed event
status via /sys/firmware/interrupts/. This is implemented using
acpi_get_event_status() and acpi_get_gpe_status(). Recently while debugging some
GPE race issues, it is found that the facility is lacking in the ability to
obtain real hardware register values, the confusing information makes
debugging difficult.

This patch modifies acpi_get_gpe_status() to return EN register values to fix
this gap. Then flags returned from acpi_get_event_status() and
acpi_get_gpe_status() are also cleaned up to reflect this change.

The old ACPI_EVENT_FLAG_SET is carefully kept to avoid regressions. It can
be deleted after we can make sure all its references are removed from OSPM
code. Lv Zheng.

Link: https://github.com/acpica/acpica/commit/e25d791e


Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>