ChangeLog: remove issue number as this is a new feature

Signed-off-by: Yanray Wang <yanray.wang@arm.com>
diff --git a/ChangeLog.d/add-aes-128bit-only.txt b/ChangeLog.d/add-aes-128bit-only.txt
index 7b7a76b..b080cac 100644
--- a/ChangeLog.d/add-aes-128bit-only.txt
+++ b/ChangeLog.d/add-aes-128bit-only.txt
@@ -2,4 +2,3 @@
    * Add support to restrict AES to 128-bit keys in order to save code size.
      A new configuration option, MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH, can be
      used to enable this feature.
-     Fixes #7376.