cpuquiet: Fix race in runnable governor

cpuquiet: Fix race in runnable governor

Fixed a race where the cpuquiet driver would call device_free() before
the governor was started, which would lead to a kernel panic because
runnables_timer was not initialized.

Introduced RUNNING state, so states are:
- DISABLED: truly disabled
- IDLE: enabled, but not polling upon request from the driver
- RUNNING: actively polling

Bug 1189042

Change-Id: I45b9ce40e61e1cfddde74ff7b2691722204045bb
Signed-off-by: Peter Boonstoppel <pboonstoppel@nvidia.com>
Reviewed-on: http://git-master/r/168803
Reviewed-by: Sang-Hun Lee <sanlee@nvidia.com>
Tested-by: Sang-Hun Lee <sanlee@nvidia.com>
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Diwakar Tundlam <dtundlam@nvidia.com>