[SCSI] fcoe: move FIP controller from fcoe_port to fcoe_interface

There is only one FIP state per net_device, so the FIP controller needs to be
moved from the per-SCSI-host fcoe_port to the per-net_device fcoe_interface
structure.

Signed-off-by: Chris Leech <christopher.leech@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>