docs(ff-a): fix specification naming

Rename the FF-A specification to:
Arm Firmware Framework for Arm A-profile

Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Change-Id: I4f9d29409d048e7a49832b95d39d2583c1fb5792
diff --git a/docs/glossary.rst b/docs/glossary.rst
index 54820e4..f4912f5 100644
--- a/docs/glossary.rst
+++ b/docs/glossary.rst
@@ -60,8 +60,8 @@
    FDT
       Flattened Device Tree
 
-   FFA
-      Firmware Framework for A-class processors
+   FF-A
+      Firmware Framework for Arm A-profile
 
    FIP
       Firmware Image Package