Send load up hint for cache rendering

cache buffer rendering supposes to utilize the cpu gap after current
frame finised and before the next frame. But it could take long and
delay the next frame start time and cause jank eventually.
Sending CPU LOAD UP hint to prevent stealing time from the next frame.

Bug: 285991802
Test: PtsUiBench QHD
Change-Id: Id619a8166ae253fef815a25a35fc4b82066144a9