Add device3

Hi guys,

resending the pull request https://github.com/autotest/virt-test/pull/1080 . Changes:
* pull request against master
* removed `class_name` checking (as lspci uses different names than qemu, eg. `IDE interface` vs.  `IDE controller`)

this patch adds support to verify info from guest lspci with info from host info qtree to pci_devices test. Please note that all test probably fails as a bit funny bug was found while developing this. When you boot VM with -S the PCI addresses of devices in bridge/switch in info qtree are messed up... (when you force autotest to run without -S the test passes).

Kind regards,
Lukáš