scsi: fcoe: move fcoe_interface_remove() out of fcoe_interface_cleanup()

This closes a possible race condition in _fcoe_create() where we drop
the rtnl_lock() before calling fcoe_interface_remove().

Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Lee Duncan <lduncan@suse.com>
Acked-by: Johannes Thumshirn <jth@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>