Ensure PMF service timestamps are properly aligned on a cache line boundary

When using more than a single service in PMF, it is necessary that the
per-service timestamps begin on a cache line boundary.  Previously it
was possible that two services shared a cache line for their
timestamps.  This made it difficult to reason about cache maintenance
operations within a single service and required a global understanding
of how all services operate.

Change-Id: Iacaae5154a7e19ad4107468e56df9ad082ee371c