x86/intel_rdt: Enable CMT and MBM on new Skylake stepping

New stepping of Skylake has fixes for cache occupancy and memory
bandwidth monitoring.

Update the code to enable these by default on newer steppings.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: stable@vger.kernel.org # v4.14
Cc: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Link: https://lkml.kernel.org/r/20180608160732.9842-1-tony.luck@intel.com