msm: hotplug: Deallocate resources when disabled

* Based on @Dorimanx and @Alucard24 idea.
* Move resource allocation to new function msm_hotplug_start()
* Create resource deallocation counterpart msm_hotplug_stop()
* Reclaim memory when msm hotplug is disabled.
* Rectify store_history_size() to reschedule only when enabled.
* Rename suspend/resume helpers to match new start/stop helpers.
* Fire up all CPUs when msm_hotplug_start() is invoked.
  This should help for speedier boot process.

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
msm: hotplug: fixed history_size modifications

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
msm: hotplug: Initialize and terminate mutex properly

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
msm: rq_stats: Disable hotplug and stats by default

* originally from @myfluxi - 920e51b116c570c871a3fda84b51c6883c202279

Userspace closed source mpdecision binary is nessecary for PowerHAL to work.
As it depends on rq_stats, let's at least disable hotplugging and stats
collection by default. /sys/devices/system/cpu/cpu0/rq-stats/hotplug_disable
is now writable, so hotplug can be reenabled.

Also, add some bits related to current cpu policy.