Handle and ignore missing information in pci.ids

If Pci_db fails to find the subdevice information for the vGPUs then the
creation of the type is ignored. It is assumed that the config file is either
corrupt or the pci.ids database in the hwdata package is in need of updating.
Merge pull request #1425 from simonjbeaumont/handle-missing-pci-ids

Handle and ignore missing information in pci.ids