Docs: threat_models: Style and refs updates

- Update the Data Flow Diagram (r/NPSE/NSPE)
- Fix TF-M version for v1.4 in version control table
- Minor cosmetics improvements

Signed-off-by: Nicola Mazzucato <[email protected]>
Change-Id: I807e8c4dcb20c191d2f15d215d511602f77b4660

Author: nicola-mazzucato-arm

docs/security/index.rst

@@ -5,7 +5,7 @@ Security
 .. toctree::
     :maxdepth: 1
 
-    Threat Model <threat_models/index>
+    Threat Models <threat_models/index>
     Security Advisories <security_advisories/index>
 
 Security Disclosures

docs/security/threat_models/generic_threat_model.rst

@@ -119,7 +119,7 @@ in the figure below. Other modules inside SPE stay in the same TOE as TF-M does.
 Valid data flows across the Trust Boundary are also shown in the figure below.
 This threat model only focuses on the data flows related to TF-M.
 
-.. figure:: overall-DFD.png
+.. figure:: overall-DFD2.png
 
 More details of data flows are listed below.
 
@@ -1161,7 +1161,7 @@ Version control
   +---------+--------------------------------------------------+---------------+
   | v1.3    | Update for validity of dual-cpu model Armv8-M    | TF-M v2.1.0   |
   +---------+--------------------------------------------------+---------------+
-  | v1.4    | Clarify mitigation strategies of threats         | TF-M v2.2.0   |
+  | v1.4    | Clarify mitigation strategies of threats         | TF-M v2.1.1   |
   +---------+--------------------------------------------------+---------------+
 
 **********

docs/security/threat_models/index.rst

@@ -5,7 +5,7 @@ Threat Models
 .. toctree::
     :maxdepth: 1
 
-    Threat model <generic_threat_model.rst>
+    TF-M Threat model <generic_threat_model.rst>
 
 --------------