qat_plugin: update loop exhausts VF driver devices

[mythi]

The update loop doing scan() exhausts devices from the VF driver pool

for _, driver := range append(dp.kernelVfDrivers, dp.dpdkDriver) {

After a while, all devices bound to kernelVfDrivers have been unbound and the plugin only scans dpdkDriver directory.

[mythi]

My expectation is that once the plugin is running, the number for <kernel VF driver> (c6xxvf below) remains constant:

$ cd /sys/bus/pci/drivers
$ while true; do echo "C62x: $(ls c6xxvf|grep 0000|wc -l), VFIO-PCI: $(ls vfio-pci|grep 0000|wc -l)" && sleep 1; done