sfxge: rename hunt filter methods, types etc. to ef10 and use for Medford

New filters types may be added, but the same machinery should be able to
handle them.

Submitted by: Mark Spender <mspender at solarflare.com>
Reviewed by: gnn
Sponsored by: Solarflare Communications, Inc.
MFC after: 2 days
Differential Revision: https://reviews.freebsd.org/D4881