Update changelog entry

Remove internal details. Add the condition of the bug.

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/ChangeLog.d/fix-parllel-cmake-build-fail.txt b/ChangeLog.d/fix-parllel-cmake-build-fail.txt
index b892eb6..4746c7b 100644
--- a/ChangeLog.d/fix-parllel-cmake-build-fail.txt
+++ b/ChangeLog.d/fix-parllel-cmake-build-fail.txt
@@ -1,6 +1,3 @@
 Bugfix
-   * Fix a build bug : when parallel out-of-box build with cmake, it raise file
-     not found error. That's due to same target is included in different sub-
-     makefiles. And cmake will call the targets in different forked `make`
-     process. As a result, the dependancy will be broken. This fix remove the
-     targets in sub-makefiles and create a global target for it.
+   * Fix a race condition in out-of-source builds with CMake when generated data
+     files are already present. Fixes #5374