PCI PM: Fix hibernation breakage on EeePC 701

Hibernation breaks on EeePC 701 as a result of attempting to put one
of its (driverless) devices into a low power state.  Avoid that by
not attepmting to power manage driverless devices during hibernation.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-and-tested-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>