The PCI Express port driver should not attempt to register service
devices that require the ability to generate interrupts if generating
interrupts is not possible.  Namely, if the port has no interrupt pin
configured and we cannot set up MSI or MSI-X for it, there is no way
it can generate interrupts and in such a case the port services that
rely on interrupts (PME, PCIe HP, AER) should not be enabled for it.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>