mel: add ADE_TIMESTAMP to the config whitelist

This prevents a full reparse from occurring every time. The parse cache was
useless since the timestamp kept changing, invalidating it.

JIRA: SB-3922

Signed-off-by: Christopher Larson <chris_larson@mentor.com>
Merge pull request #372 from kergoth/sb-3922

mel: add ADE_TIMESTAMP to the config whitelist

Looks good.