SF: RenderEngine::primeCache should not be called as SCHED_FIFO

RenderEngine::primeCache is quite long and as such can't run at
SCHED_FIFO.

Test: boot the device and observe RenderEngine::primeCache timing
Bug: 190529454
Change-Id: I9024c4a365efde717bd4cc9f382d1729a2e2446f
11 files changed