Backport #1949 into mbedtls-2.7

Signed-off-by: Jeffrey Martin <Jeffrey_Martin@rapid7.com>
diff --git a/ChangeLog b/ChangeLog
index 005573d..09ab3db 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -5,6 +5,10 @@
 Bugfix
    * Run the AD too long test only if MBEDTLS_CCM_ALT is not defined.
      Raised as a comment in #1996.
+   * Extend register cleanup needed on MIPS assembly optimizations. Adds hi, lo
+     registers hints to the compiler for usage with the embedded MIPS assembly.
+     Reported in #1722, fix suggested by @aurel32 and submitted
+     by Jeffrey Martin, #1949.
 
 = mbed TLS 2.7.9 branch released 2018-12-21