Update specifications section

Update the documentation on supported specifications:
  - clean up PSA related info.
  - add a page on FF-A

Change-Id: I68e8e7762bdce765f38acf503d1d762deb104cc7
Signed-off-by: Gyorgy Szing <Gyorgy.Szing@arm.com>
diff --git a/docs/project/glossary.rst b/docs/project/glossary.rst
index da907b4..74356c0 100644
--- a/docs/project/glossary.rst
+++ b/docs/project/glossary.rst
@@ -23,12 +23,21 @@
     ACLE
         `Arm C language extensions`_
 
+    PSA
+        `Platforn Security Arhitecture`_
+
+    FF-A
+        `Firmware Framework for A`_
+
 
 --------------
 
 .. _`Arm Glossary`: https://developer.arm.com/support/arm-glossary
 .. _`Linux Coding Style`: https://www.kernel.org/doc/html/v4.10/process/coding-style.html
 .. _`Arm C language extensions`: https://developer.arm.com/documentation/101028/0012/?lang=en
+.. _`Platforn Security Arhitecture`:  https://developer.arm.com/architectures/security-architectures/platform-security-architecture
+.. _`Firmware Framework for A`: https://developer.arm.com/docs/den0077/latest
+
 
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