IB/isert: Fix incorrect release of isert connection

The ib_isert module is releasing the isert connection both in
isert_wait_conn() handler as well as isert_free_conn() handler.
In isert_wait_conn() handler, it is expected to wait for iSCSI
session logout operation to complete. It should free the isert
connection only in isert_free_conn() handler.

When a bunch of iSER target is cleared, this issue can lead to
use-after-free memory issue as isert conn is twice released

Fixes: b02efbfc9a05 ("iser-target: Fix implicit termination of connections")
Reviewed-by: Sagi Grimberg <[e-mail]>
Signed-off-by: Saravanan Vajravel <[e-mail]>
Signed-off-by: Selvin Xavier <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Leon Romanovsky <[e-mail]>

drivers/infiniband/ulp/isert/ib_isert.c

···
 	isert_put_unsol_pending_cmds(conn);
 	isert_wait4cmds(conn);
 	isert_wait4logout(isert_conn);
-
-	queue_work(isert_release_wq, &isert_conn->release_work);
 }
 
 static void isert_free_conn(struct iscsit_conn *conn)