Squashed commits:
1. x86_64: qemu: implement pci-e functions and enumerate pci-e devices on boot
2. virt: add qemu pci-testdev driver
3. pcie: types array should be null terminated
4. pcie: enable don't take flags, hardcoded enabling flags
5. pcie: checking bar > 4 for 64bit bars are sufficient
6. pcie: qemu: remove not used header
7. pcie: qemu: return -EINVAL if buffer argument is NULL
8. pcie: make pcie enumerate routine as common instead of architecture dependent
9. pcie: cosmetic changes to fit check tools
10. pcie: create MSI/MSIX related marcos and simplify the msi/msix routines
