qdutils: Refactor idletimeout fallback mechanism.

1. Use kernel timer interrupt to signal about the timeout to
   Invalidator thread and fallback to GPU composition.
2. This implementation avoids waking up the Invalidator thread for
   every idletimeout value during continuous update.

Change-Id: I4370f10a0ca06b5cb1e7bdcb047e9c8daec51afb
4 files changed