TouchpadInputMapper: add more log lines when producing atoms

The previous log line isn't appearing in cases where the test flakes, so
add some more to confirm whether the issue is with getting the pull
request or acquiring the lock.

Bug: 329725372
Test: check the log line appears when running the test:
      $ atest 'android.input.cts.hostside.InputAtomsTest#testTouchpadUsageAtom_FingerAndPalmCounts'
Change-Id: Ic062a5fe5db905c4691147a1267600981b9017e8