sched: add preference for prev and sibling CPU in HMP task placement

At present HMP task placement algorithm places wake-up task on any lowest
power cost CPU in the system even if the task's previous CPU is also one
of the lowest power cost CPU.  Placing task on the previous CPU can reduce
cache bouncing.

Add a bias towards the task's previous CPU and CPU in the same cache domain
with previous CPU.

Change-Id: Ieab3840432e277048058da76764b3a3f16e20c56
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>