igt/gem_mocs_settings: Use i915_pmu to measure rc6 residency

Use the perf pmu interface for lowlevel rc6 measurement, hopefully for
greater stability.

v2: Fix timeout to run for 1s, not one pass!

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
3 files changed