sched: run sync wakeup small tasks on current CPU when possible

During a sync wakeup of a small task, if the waker CPU has only
the waker task running, run the waking task on that same CPU.
Cache hotness may outweigh considerations of CPU differences in
this scenario.

Change-Id: I5df9bafd29424ccecb98abe63eeec0458be9e175
Signed-off-by: Steve Muckle <smuckle@codeaurora.org>