Add changelog entry for chunked associated data in GCM.
@@ -15,3 +15,5 @@ Features
* The multi-part GCM interface (mbedtls_gcm_update() or
mbedtls_cipher_update()) no longer requires the size of partial inputs to
be a multiple of 16.
+ * The multi-part GCM interface now supports chunked associated data through
+ multiple calls to mbedtls_gcm_update_ad().
