PCI: Use add_list in pcie hotplug path.

We need add size for hot plug path when pluging in hotplug chassis
without cards.

-v2: change descriptions. make it applicable after "pci: Check bridge
     resources after resource allocation."

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>