Remove ATM protocol support.

FreeBSD ditched it about 6 years ago. Also, I'm not sure if this ever
worked on x86_64.
kernel/ral: Switch back to using pcidevs.h.

It was lost with feb94d24033db5d8fe8e5e4807103d48f3638ceb.
pcidevs: Remove some IDs we don't use.