ACPI: create /sys/firmware/acpi/interrupts

See Documentation/ABI/testing/sysfs-firmware-acpi

Based-on-original-patch-by: Luming Yu <luming.yu@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>