This is a follow-on to 'vPCI: avoid bogus "overlap in extended cap list"
warnings', addressing further issues noted there.

v2: New first patch and significantly re-worked 2nd one. See there.

1: PCI: handle PCI->PCIe bridges as well in alloc_pdev()
2: PCI: determine whether a device has extended config space
3: PCI: don't look for ext-caps when there's no extended cfg space
4: vPCI/DomU: really no ext-caps without extended config space

Jan