ANDROID: sched: Add vendor hook for rt util update

Vendor may have need to track rt util.

The hook is expected to always be called in set_next_task_rt() unlike
update_rt_rq_load_avg().

Bug: 344826816
Bug: 201261299
Signed-off-by: Rick Yiu <rickyiu@google.com>
Change-Id: I2f4e5142c6bc8574ee3558042e1fb0dae13b702d
(cherry picked from commit 2490ab50)
[Trivial conflict in include/trace/hooks/sched.h due to new code added.
And in vendor_hooks.c due to code ordering.]
Signed-off-by: Qais Yousef <qyousef@google.com>