intel_enable_rc6() is used to check if we can compute the RC6 residency
in the sysfs code. Disable this for platforms older than Ironlake.
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>