If I recall there is support for QLogic FC adapters built in. I saw the drivers load on a test box. But I'm a solaris guy and the structure of freebsd is way different. I could not find any separate module files sitting around. To the OP, iSCSI does not run over FC in any nice fashion. You would first need to run IP over FC, then export an iSCSI target over that new network interface. But in 10 years of dealing with FC, I've only seen 2 people have sensible / legit deployments of IP over FC. Those people did not run iSCSI over those interfaces though.
Now if you are looking for FC target mode, that's a different thing.