Fix typos in changelog

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/ChangeLog b/ChangeLog
index f0dc08c..3e3dc10 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -11,8 +11,8 @@
 API changes
    * Mbed TLS 3.4 introduced support for omitting the built-in implementation
      of ECDSA and/or EC J-PAKE when those are provided by a driver. However,
-     their was a flaw in the logic checking if the built-in implementation, in
-     that if failed to check if all the relevant curves were supported by the
+     there was a flaw in the logic checking if the built-in implementation, in
+     that it failed to check if all the relevant curves were supported by the
      accelerator. As a result, it was possible to declare no curves as
      accelerated and still have the built-in implementation compiled out.
      Starting with this release, it is necessary to declare which curves are