Changelog entry for the ARIA_ALT and CAMELLIA_ALT fixes

Fix ARMmbed/mbed-os#14694

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/ChangeLog.d/aria-alt.txt b/ChangeLog.d/aria-alt.txt
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+++ b/ChangeLog.d/aria-alt.txt
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+Bugfix
+   * Fix some issues affecting MBEDTLS_ARIA_ALT implementations: a misplaced
+     directive in a header and a missing initialization in the self-test.
+   * Fix a missing initialization in the Camellia self-test, affecting
+     MBEDTLS_CAMELLIA_ALT implementations.