This patch adds ABI document for the following sysfs file: /sys/bus/pci/devices/.../d3cold_allowed Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Rafael J. Wysocki <rjw@sisk.pl>