CTR_DRBG documentation: add changelog entry
This is a documentation-only change, but one that users who care about
NIST compliance may be interested in, to review if they're using the
module in a compliant way.
diff --git a/ChangeLog b/ChangeLog
index 6ba9a5a..70488e2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -73,6 +73,8 @@
Changes
* Add unit tests for AES-GCM when called through mbedtls_cipher_auth_xxx()
from the cipher abstraction layer. Fixes #2198.
+ * Clarify how the interface of the CTR_DRBG module relates to
+ NIST SP 800-90A.
= mbed TLS 2.16.3 branch released 2019-09-06