Remove unnecessary changelog

Signed-off-by: Paul Elliott <paul.elliott@arm.com>
diff --git a/ChangeLog.d/fix_bignum_unchecked_return.txt b/ChangeLog.d/fix_bignum_unchecked_return.txt
deleted file mode 100644
index 1c32da8..0000000
--- a/ChangeLog.d/fix_bignum_unchecked_return.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-Bugfix
-   * Fix unchecked return in bignum module.