Label /proc/sys/kernel/sched_schedstats.

This allows init to write to it, which it does for atrace.

Bug: 72643420
Test: Boot two devices, observe no denials, test atrace.
Change-Id: I6810e5dcdfaff176bd944317e66d4fe612ccebed

private/genfs_contexts

@@ -51,6 +51,7 @@ genfscon proc /sys/kernel/sched_child_runs_first u:object_r:proc_sched:s0
 genfscon proc /sys/kernel/sched_latency_ns u:object_r:proc_sched:s0
 genfscon proc /sys/kernel/sched_rt_period_us u:object_r:proc_sched:s0
 genfscon proc /sys/kernel/sched_rt_runtime_us u:object_r:proc_sched:s0
+genfscon proc /sys/kernel/sched_schedstats u:object_r:proc_sched:s0
 genfscon proc /sys/kernel/sched_tunable_scaling u:object_r:proc_sched:s0
 genfscon proc /sys/kernel/sched_wakeup_granularity_ns u:object_r:proc_sched:s0
 genfscon proc /sys/kernel/sysrq u:object_r:proc_sysrq:s0