Fill bdf field of the host_info structure in ENA

The host info bdf field is the abbreviation for the bus, device,
function of the PCI on which the device is being attached to.

Now the driver is filling information about that using FreeBSD RID
resource.

Submitted by: Michal Krawczyk <mk@semihalf.com>
Obtained from: Semihalf
Sponsored by: Amazon, Inc.