Add ChangeLog entry for CCM_ALT

Edit the CMAC_ALT ChangeLog entry to mention CCM_ALT which was added
in a sister PR and is being merged together.

Use full name rather than Github id as attribution.

Move the entry under "Features" for better consistency with historical
practice.

ChangeLog

diff --git a/ChangeLog b/ChangeLog
index 6377e7f..d9e9dc8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -18,6 +18,8 @@
      line arguments.
    * New unit tests for timing. Improve the self-test to be more robust
      when run on a heavily-loaded machine.
+   * Add alternative implementation support for CCM and CMAC (MBEDTLS_CCM_ALT,
+     MBEDTLS_CMAC_ALT). Submitted by Steve Cooreman, Silicon Labs.
 
 New deprecations
    * Deprecate usage of RSA primitives with non-matching key-type
@@ -71,8 +73,6 @@
    * Extend cert_write example program by options to set the CRT version
      and the message digest. Further, allow enabling/disabling of authority
      identifier, subject identifier and basic constraints extensions.
-   * Add hardware acceleration support for cmac, with the configuration definition
-     of `MBEDTLS_CMAC_ALT`. Submitted by stevew817
 
 = mbed TLS 2.6.0 branch released 2017-08-10