power: Ignore interaction boost sequence in a short period

 * When slowly, but continuously scrolling, a sequence of zero duration
   boosts are fired by the framework. They quickly fill up the internal
   limitation of MPCTL, as a result all incoming boosts get ignored.
 * Fixing the following logspam:
    ANDR-PERF-MPCTL: Active req limit reached, No optimizations performed
 * This restores cm-14.1 behavior.

Change-Id: I977e844935539a4598a749c77f4c0934ca93a2b7