iscsi-target: Remove no-op from iscsit_tpg_del_portal_group

This patch removes a no-op iscsit_clear_tpg_np_login_threads() call
in iscsit_tpg_del_portal_group(), which is unnecessary because
iscsit_tpg_del_portal_group() can only ever be removed from configfs
once all of the child network portals have been released.

Also, go ahed and make iscsit_clear_tpg_np_login_threads() declared
as static.

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/iscsi/iscsi_target_tpg.c b/drivers/target/iscsi/iscsi_target_tpg.c
index ca18118..7112676 100644
--- a/drivers/target/iscsi/iscsi_target_tpg.c
+++ b/drivers/target/iscsi/iscsi_target_tpg.c
@@ -188,7 +188,7 @@
 	iscsit_reset_np_thread(tpg_np->tpg_np, tpg_np, tpg, shutdown);
 }
 
-void iscsit_clear_tpg_np_login_threads(
+static void iscsit_clear_tpg_np_login_threads(
 	struct iscsi_portal_group *tpg,
 	bool shutdown)
 {
@@ -275,8 +275,6 @@
 	tpg->tpg_state = TPG_STATE_INACTIVE;
 	spin_unlock(&tpg->tpg_state_lock);
 
-	iscsit_clear_tpg_np_login_threads(tpg, true);
-
 	if (iscsit_release_sessions_for_tpg(tpg, force) < 0) {
 		pr_err("Unable to delete iSCSI Target Portal Group:"
 			" %hu while active sessions exist, and force=0\n",