Do not use scheduling service in cameraservice.

Since the cameraserver sets the RLIMIT_RTPRIO as 10 in it's
init.rc file, cameraservice can boost the priority of camera
request thread using direct calls till that limit instead of
using scheduling service.

Bug: 231557017
Test: Test using a simple camera2 ndk program which opens the camera and
capture a still image.

Change-Id: Iedba796f9a74e87f9d93f243617ec4895206a3cb