User can now configure the list of device classes to detect, either via
a configuration file or by using the --options command line flag.
An example of a command line flag to detect all network controllers and
("main class 0x02) and VGA display controllers ("main" class 0x03 and
subclass 0x00) would be:
--options='{"sources": {"pci": {"deviceClassWhitelist": ["02", "0300"] } } }'
This feature source detects the presence of PCI devices. At the moment,
it only advertises GPUs and accelerator cards, i.e. device classes 0x03,
0x0b40 and 0x12.
The label format is:
node.alpha.kubernetes-incubator.io/nfd-pci-<device label>.present
where <device label> is composed of raw PCI IDs:
<class id>_<vendor id>
