ANDROID: sched/core: Move en/dequeue hooks before related callbacks

Vendors want to get en/dequeueing information and update
some vendor-managed data to modifiy DVFS or scheduling behavior.

But in the current hooking positions, vendors get the information
after all behaviors they want to modify are done.

So need to move the hooks before en/dequeue callbacks
to achieve the "true" goals.

Bug: 183543978

Signed-off-by: Choonghoon Park <choong.park@samsung.com>
Change-Id: I12f8e77054d12a855df10ca9d13a52d417343666