drivers: cpuquiet: Fix runnable gov device_busy

drivers: cpuquiet: Fix runnable gov device_busy

On device_busy, the runnable governor stops its sample timer and cancels
any queued runnable_work. However, it is possible for the cpuquiet
platform driver to call device_busy on cpuquiet_quiesence/wake_cpu calls
which can be invoked from the queued runnable_worker thread. This will
lead to the runnable_worker thread waiting infinitely on it self
finishing in cancel_work_sync.

Fix this by removing the cancel_work_sync call as it isn't necessary
because the worker doesn't requeue it self. Stopping the timer is
sufficient.

Bug 200002511

Change-Id: Ic69061b12d4dbb96b259ed9b62a0475271bd36d0
Signed-off-by: Sai Gurrappadi <sgurrappadi@nvidia.com>
(cherry picked from commit b9a2a2cfa91d14935fdef626517d738399af4e4d)
Reviewed-on: http://git-master/r/415315
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Diwakar Tundlam <dtundlam@nvidia.com>
Reviewed-by: Kerwin Wan <kerwinw@nvidia.com>