Add PNP info to PCI attachment of ena driver

Make unsigned values uint16_t for pnp table. They are properly
uint16_t befause they are 16-bit PCI IDs. The PNP_INFO language has no
type for bare unsigned.

Reviewed by: imp, chuck
Submitted by: Lakhan Shiva Kamireddy <lakhanshiva@gmail.com>
Sponsored by: Google, Inc. (GSoC 2018)
Pull Request: https://github.com/bsdimp/freebsd/pull/5