Add a changelog entry

Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/ChangeLog.d/fix_timing_alt.txt b/ChangeLog.d/fix_timing_alt.txt
new file mode 100644
index 0000000..38ff595
--- /dev/null
+++ b/ChangeLog.d/fix_timing_alt.txt
@@ -0,0 +1,5 @@
+Bugfix
+   * Fix a build issue when defining MBEDTLS_TIMING_ALT and MBEDTLS_SELF_TEST.
+     The library would not link if the user didn't provide an external selftest function.
+     The self-test is now provided regardless of the choice of internal/alternative
+     timing implementation. Fixes #6923.