sched: fair: Always try to use energy efficient cpu for wakeups

Always try to use energy efficient cpu in case of energy aware
scheduler.

Change-Id: I7d849b8cc230d8d4b929f0951ea1c6f8c201dd40
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>