ANDROID: sched: add hook point in do_sched_yield()

When a task yields, it relinquishes the cpu and
scheduler is tasked to find another task.
However our vendor scheduler logic implementation
could return the same task leading to a loop where
the yielded task gets to run back, so add hook point
in do_sched_yield() for vendor can do some work
before task is scheduled.

Bug: 205804537
Change-Id: I6528c3f4b0ee360559ef9c97cb1eb2b2d1357870
Signed-off-by: Tengfei Fan <quic_tengfan@quicinc.com>