CameraService: Use SCHED_FIFO for request queue thread in HFR

- Move SchedulingPolicyService from audioservice to mediautils

- When starting up a high speed stream config, set request queue thread
  to SCHED_FIFO using SchedulingPolicyService

Bug: 24227252
Change-Id: I224b59142bd111caf563779f55cddd62385b9bac
diff --git a/services/camera/libcameraservice/device3/Camera3Device.h b/services/camera/libcameraservice/device3/Camera3Device.h
index 9d3c533..402cb1d 100644
--- a/services/camera/libcameraservice/device3/Camera3Device.h
+++ b/services/camera/libcameraservice/device3/Camera3Device.h
@@ -161,6 +161,8 @@
     static const nsecs_t       kActiveTimeout     = 500000000;  // 500 ms
     static const size_t        kInFlightWarnLimit = 20;
     static const size_t        kInFlightWarnLimitHighSpeed = 256; // batch size 32 * pipe depth 8
+    // SCHED_FIFO priority for request submission thread in HFR mode
+    static const int           kConstrainedHighSpeedThreadPriority = 3;
 
     struct                     RequestTrigger;
     // minimal jpeg buffer size: 256KB + blob header