There are two idle injection implementation in the Linux kernel. One
via intel_powerclamp and the other using powercap/idle_inject. Both
implementation end up in calling play_idle* function from a FIFO
priority thread. Both can't be used at the same time.

It is better to use one idle injection framework for better
maintainability. In this way, there is only one caller for play_idle.

Here powercap/idle_inject can be used for both per-core and for system
wide idle injection. This framework has a well defined interface which
allow registry for per-core or for all CPUs (system wide).

This reduces code complexity in the intel powerclamp driver as all the
per CPU kthreads, delayed work and calls to play_idle can be removed.

The changes include:
 - Remove unneeded include files
 - Remove per CPU kthread workers: balancing_work and idle_injection_work.
 - Reuse the compensation related code by moving from previous worker
   thread to idle_injection callback.
 - Adjust the idle_duration and runtime by using powercap/idle_inject
   interface.
 - Remove all variables, which are not required once powercap/idle_inject
   is used.
 - Add mutex to avoid race during removal of idle injection during module
   unload and user action to change idle inject percent. Also for
   protection during dynamic adjustment of run and idle time from
   update() callback.
 - Remove online/offline callbacks to designate control CPU
 - Use cpu_present_mask global variable for CPU mask
 - Remove hot plug locks
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>