docs(security): security advisory for CVE-2022-23960

Signed-off-by: Bipin Ravi <bipin.ravi@arm.com>
Change-Id: I17b0847ff71e4a291bf7ba41fd71fe08c400b5e8
diff --git a/docs/security_advisories/index.rst b/docs/security_advisories/index.rst
index ce2c843..887b06a 100644
--- a/docs/security_advisories/index.rst
+++ b/docs/security_advisories/index.rst
@@ -14,3 +14,4 @@
    security-advisory-tfv-6.rst
    security-advisory-tfv-7.rst
    security-advisory-tfv-8.rst
+   security-advisory-tfv-9.rst