Docs: Tidy up the security section

Signed-off-by: Anton Komlev <anton.komlev@arm.com>
Change-Id: I71cac0e19434def9c73859275b3130798f2efd0d
diff --git a/docs/security/threat_models/index.rst b/docs/security/threat_models/index.rst
index 227d4d4..671c1be 100644
--- a/docs/security/threat_models/index.rst
+++ b/docs/security/threat_models/index.rst
@@ -1,12 +1,8 @@
-Threat Models
-=============
-
 .. toctree::
     :maxdepth: 1
-    :glob:
 
-    *
+    Threat model <generic_threat_model.rst>
 
 --------------
 
-*Copyright (c) 2020, Arm Limited. All rights reserved.*
+*Copyright (c) 2023, Arm Limited. All rights reserved.*