Add a dummy entry for the 70220 event tag

This will prevent services from reaching out to logd if this tag is
present in the event log.

Bug: 64734187
Test: tree-hugger
Merged-In: If117e1c0cfa678af4190913f0ca87f4e92c54373
Change-Id: If117e1c0cfa678af4190913f0ca87f4e92c54373
(cherry picked from commit dcc4b2bb)