Remove PciDeviceList usage in pci manager

Pci manager keeps a PciDeviceList and even try to append
object to the list. This is not correct, as the ObjectList
is designed as immutable, although the objects in the list is
mutable. We should simply use a list to keep devices.

Closes-Bug: #1273803

Change-Id: Ie80b6f5f47a1d2d2e20aadb4779be142c17b5b38
Merge "Remove PciDeviceList usage in pci manager"