drm/i915/pmu: "Frequency" is reported as accumulated cycles

drm/i915/pmu: "Frequency" is reported as accumulated cycles

We report "frequencies" (actual-frequency, requested-frequency) as the
number of accumulated cycles so that the average frequency over that
period may be determined by the user. This means the units we report to
the user are Mcycles (or just M), not MHz.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191109105356.5273-1-chris@chris-wilson.co.uk