[$] The pseudo cpuidle driver

The purpose of a cpuidle governor is to decide which idle state a CPUshould go into when it has no useful work to do; the cpuidle driverthen actually puts the CPU into that state. But, at the 2020 Power Management and Schedulingin the Linux Kernel summit (OSPM), Abhishek Goel presented a newcpuidle driver that doesn't actually change the processor's power state at all.Such a driver will clearly save no power, but it can be quite useful as atool for evaluating and debugging cpuidle policies.