docs(errata_abi): document the errata abi changes

Updated errata ABI feature enable flag and the errata non-arm
interconnect based flag, the default values for when the
feature is not enabled.

Change-Id: Ieb2144a1bc38f4ed684fda8280842a18964ba148
Signed-off-by: Sona Mathew <SonaRebecca.Mathew@arm.com>
(cherry picked from e5d9b6f0bfa6f840ad1c5c72c455fe9a7c0dcaa8)
diff --git a/docs/glossary.rst b/docs/glossary.rst
index e6b0239..89113c0 100644
--- a/docs/glossary.rst
+++ b/docs/glossary.rst
@@ -70,6 +70,9 @@
    EHF
       Exception Handling Framework
 
+   ERRATA_ABI
+      Errata management firmware interface
+
    FCONF
       Firmware Configuration Framework