timer: Queue timers on least power cpu

There is potential power benefit by offloading timer activity to cpus
of lesser power cost (power cluster). Both high-res and low-res timers
that are not pinned to one cpu are now enqueued on an online CPU
found in least shallow C-state in power-cluster. Prefer the current
CPU in case of a tie.

Change-Id: I2cea26c76972b566dfbfed084e377811a8784172
Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>