DLPAR: enhance test to support multiple pci ids for test

[abdhaleegit]

Allow user to give multiple PCI input example for NIC and FC both

Now test only accepts single PCI ID pci_device: "0001:00:01"

1. make sure test takes multiple pci ids like pci_device: "0001:00:01 0002:00:00" and perform dlpar in loop
2. if it is a NIC adapter, check for network connectivity after each dlpar
3. if it is a FC adapter, check for disk recovered after dlpar

https://github.com/open-power/op-test/blob/master/testcases/OpTestDlparIO.py

Refer to https://github.com/avocado-framework-tests/avocado-misc-tests/blob/master/io/pci/pci_hotplug.py for old code