drm/i915: Only apply the jump to the "efficient RPS" frequency on startup

Currently we apply the jump to rpe if we are below it and the GPU needs
more power. For some GPUs, the rpe is 75% of the maximum range causing
us to dramatically overshoot low power applications *and* unable to
reach the low frequency that can most efficiently deliver their
workload.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170210150348.22146-3-chris@chris-wilson.co.uk


Reviewed-by: Radoslaw Szwichtenberg <radoslaw.szwichtenberg@intel.com>