Re-apply r190640.

• Restore local change to include <net/bpf.h> inside pcap.h.

This fixes ports build problems.

• Update local copy of dlt.h with new DLT types.
• Revert no longer needed <net/bpf.h> includes which were added

as part of r334277.

Suggested by: antoine@, delphij@, np@
MFC after: 3 weeks
Sponsored by: Mellanox Technologies