sched: Use absolute scale for notifying governor

Make the tunables used for deciding the need for notification to be on
absolute scale. The earlier scale (in percent terms relative to
cur_freq) does not work well with available range of frequencies. For
example, 100% tunable value would work well for lower range of
frequencies and not for higher range. Having the tunable to be on
absolute scale makes tuning more realistic.

Change-Id: I35a8c4e2f2e9da57f4ca4462072276d06ad386f1
Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>