cpuquiet: Remove synchronization from runnables_work_func()

cpuquiet: Remove synchronization from runnables_work_func()

runnables_stop() can deadlock when cancel_work_sync() waits for the
work function to end and the work function blocks on the same lock
held by runnables_stop().

Removing the locks from runnables_work_func() fixes this. This should
be safe because runnables_lock protects runnables_state and
runnables_work_func() only reads runnables_state. Also, the functions
that change state to DISABLED do a cancel_work_sync() to guarantee the
work function stopped running.

Bug 1215668

Change-Id: I70617b3b0fc81db8555869e67e3b11652af8d94c
Signed-off-by: Peter Boonstoppel <pboonstoppel@nvidia.com>
Reviewed-on: http://git-master/r/193881
Reviewed-by: Mandar Padmawar <mpadmawar@nvidia.com>
Tested-by: Mandar Padmawar <mpadmawar@nvidia.com>