Log less on negative deltas in kernel CPU time readers

Logging the second, third etc. negative delta detected for a single
UID increases logging without a clear debugging benefit vs. just
noting the UIDs with at least one negative delta.

Bug: 182272121
Change-Id: Ia7c6994203493467d07eeb8092da1679864dc89e
Signed-off-by: Connor O'Brien <connoro@google.com>