cpufreq: intel_pstate: Fix object lifecycle issue in update_qos_request()

In the Linux kernel, the following vulnerability has been resolved: cpufreq: intel_pstate: Fix object lifecycle issue in update_qos_request() The cpufreq_cpu_put() call in update_qos_request() takes place too early because the latter subsequently calls freq_qos_update_request() that indirectly accesses the policy object in question through the QoS request object passed to it. Fortunately, update_qos_request() is called under intel_pstate_driver_lock, so this issue does not matter for changing the intel_pstate operation mode, but it theoretically can cause a crash to occur on CPU device hot removal (which currently can only happen in virt, but it is formally supported nevertheless). Address this issue by modifying update_qos_request() to drop the reference to the policy later.