Update changelog to cover #4488

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/ChangeLog b/ChangeLog
index d10bd37..dc03d48 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -155,6 +155,9 @@
    * mbedtls_ssl_get_session_pointer() has been removed, and
      mbedtls_ssl_{set,get}_session() may now only be called once for any given
      SSL context.
+   * The mode parameter has been removed from the RSA decrypt functions
+     mbedtls_pk_rsa_alt_decrypt_func(), mbedtls_rsa_pkcs1_decrypt(),
+     mbedtls_rsa_pkcs1_decrypt(), mbedtls_rsa_rsaes_oaep_decrypt().
 Default behavior changes
    * Enable by default the functionalities which have no reason to be disabled.