According to the PCI Firmware Specification Revision 3.0 section 4.5, _OSC
should only be called on a root brdige.  Here is the relevant passage: "The
_OSC interface defined in this section applies only to Host Bridge ACPI
devices that originate PCI, PCI-X, or PCI Express hierarchies". Changed the
code to find the parent root bridge of the device and call _OSC on that.
Signed-off-by: NAndrew Patterson <andrew.patterson@hp.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>