doc: remove usage of PSA wording

FF-A specification is shortcut for "Arm Firmware Framework for Armv8-A".

Change-Id: Iec52e5cf781bddd600957ce6f5685102c79768f1
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/docs/Architecture.md b/docs/Architecture.md
index 9c086eb..7bba78e 100644
--- a/docs/Architecture.md
+++ b/docs/Architecture.md
@@ -17,7 +17,7 @@
 
 *   Means for VMs to communicate with each other through message passing and
     memory sharing, according to the Arm
-    [Platform Security Architecture Firmware Framework for Arm v8-A (PSA FF-A)](https://developer.arm.com/docs/den0077/a).
+    [Arm Firmware Framework for Armv8-A (FF-A)](https://developer.arm.com/documentation/den0077/latest/).
 *   Emulation of some basic hardware features such as timers.
 *   A simple paravirtualised interrupt controller for secondary VMs, as they
     don't have access to hardware interrupts.