docs: Add PSA Crypto SP security assessment

Add the security assessment of the PSA Crypto SP.

Change-Id: Icc47b9947854e4bdb6ab80a687a7c925aad21e8c
Signed-off-by: Imre Kis <imre.kis@arm.com>
Signed-off-by: Gyorgy Szing <gyorgy.szing@arm.com>
diff --git a/docs/security/threat-assessment/index.rst b/docs/security/threat-assessment/index.rst
index 7114e1a..5c34cb9 100644
--- a/docs/security/threat-assessment/index.rst
+++ b/docs/security/threat-assessment/index.rst
@@ -8,6 +8,7 @@
     :caption: Secure Partitions
 
     psa-storage-threat-assessment
+    crypto-service-threat-assessment
 
 
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