OPP layer now supports freeing of OPPs and we should free them once they aren't
useful anymore.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Tested-by: NStefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>