TFMV-1: Add Stack seal advisory

Signed-off-by: Soby Mathew <soby.mathew@arm.com>
Change-Id: Ifbadc2d59cfb91e3ae09910a270d2358e378b3e6
diff --git a/docs/reference/security_advisories/index.rst b/docs/reference/security_advisories/index.rst
new file mode 100644
index 0000000..8511908
--- /dev/null
+++ b/docs/reference/security_advisories/index.rst
@@ -0,0 +1,12 @@
+Security Advisories
+===================
+
+.. toctree::
+    :maxdepth: 1
+    :glob:
+
+    *
+
+--------------
+
+*Copyright (c) 2020, Arm Limited. All rights reserved.*