PCIe: portdrv: call pci_disable_device during remove

The PCIe port driver calls pci_enable_device when registering
ports, but never calls pci_disable_device during removal.

Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>