iscsi-target: Fix NULL dereference on allocation failure

This patch fixes a bug in iscsi_target_init_negotiation() where
the "goto out" path dereferences "login" which is NULL upon a
memory allocation failure.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/iscsi/iscsi_target_nego.c

@@ -978,7 +978,7 @@ struct iscsi_login *iscsi_target_init_negotiation(
 		pr_err("Unable to allocate memory for struct iscsi_login.\n");
 		iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
 				ISCSI_LOGIN_STATUS_NO_RESOURCES);
-		goto out;
+		return NULL;
 	}
 
 	login->req = kzalloc(ISCSI_HDR_LEN, GFP_KERNEL);