iscsit: remove incorrect unlock in iscsit_build_sendtargets_resp

Fix a potential multiple spin-unlock -> deadlock scenario during the
overflow check within iscsit_build_sendtargets_resp() as found by
sparse static checking.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/iscsi/iscsi_target.c

@@ -3274,7 +3274,6 @@ static int iscsit_build_sendtargets_response(struct iscsi_cmd *cmd)
 		len += 1;
 
 		if ((len + payload_len) > buffer_len) {
-			spin_unlock(&tiqn->tiqn_tpg_lock);
 			end_of_buf = 1;
 			goto eob;
 		}