cpufreq/x86: Enable __getload() helper for Medfield-x86 platform

cpufreq/x86: Enable __getload() helper for Medfield-x86 platform

BZ: 31189

Enable the hardware based load calculation for the Medfield x86-HT platform.
This makes sure that the on-demand governor responds correctly to the load
based on the physical core and not the logical siblings

Change-Id: Iaeaf5f154ca955f3e8cfe09c052f23913edbf5a1
Signed-off-by: Chuan A Wang <chuan.a.wang@intel.com>
Signed-off-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: Ke Chen <ke.chen@intel.com>
Signed-off-by: Sundar Iyer <sundar.iyer@intel.com>
Reviewed-on: http://android.intel.com:8080/48470
Reviewed-by: Martin, LoicX <loicx.martin@intel.com>
Tested-by: Martin, LoicX <loicx.martin@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>