[PORT FROM R2] mid_pmu: create a sysfs entry to set all the south complex devices...

[PORT FROM R2] mid_pmu: create a sysfs entry to set all the south complex devices in D0i0

BZ: 16961

This patch create a sysfs entry /sys/module/mid_pmu/parameters/pmu_driver_state
Doing, echo "off" > /sys/module/mid_pmu/parameters/pmu_driver_state will
set all the south complex devices in D0i0 state and any further request
to set any south complex device in some other low power state will
be ignored.

Removed the code corresponding to echo "on" path as we are always supposed
to do reboot after issuing echo "off".

Change-Id: I2f75b9fbb042218105aa58c5d709af4c8f0d6754
Orig-Change-Id: I94f1c85ee6cd44b74c455d0dd5a7b35e1e86b512
signed-off-by: Dyut Kumar Sil
Reviewed-on: http://android.intel.com:8080/29309
Reviewed-by: Martin, LoicX <loicx.martin@intel.com>
Reviewed-by: Mansoor, Illyas <illyas.mansoor@intel.com>
Tested-by: Martin, LoicX <loicx.martin@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>