target: Drop unnecessary core_tpg_register TFO parameter

This patch drops unnecessary target_core_fabric_ops parameter usage
for core_tpg_register() during fabric driver TFO->fabric_make_tpg()
se_portal_group creation callback execution.

Instead, use the existing se_wwn->wwn_tf->tf_ops pointer to ensure
fabric driver is really using the same TFO provided at module_init
time.

Also go ahead and drop the forward TFO declarations tree-wide, and
handling the special case for iscsi-target discovery TPG.

Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/tcm_fc/tfc_conf.c

@@ -47,8 +47,6 @@
 
 #include "tcm_fc.h"
 
-static const struct target_core_fabric_ops ft_fabric_ops;
-
 static LIST_HEAD(ft_wwn_list);
 DEFINE_MUTEX(ft_lport_lock);
 
@@ -282,8 +280,7 @@ static struct se_portal_group *ft_add_tpg(
 		return NULL;
 	}
 
-	ret = core_tpg_register(&ft_fabric_ops, wwn, &tpg->se_tpg,
-				SCSI_PROTOCOL_FCP);
+	ret = core_tpg_register(wwn, &tpg->se_tpg, SCSI_PROTOCOL_FCP);
 	if (ret < 0) {
 		destroy_workqueue(wq);
 		kfree(tpg);