sched_ext: Mark racy bitfields to prevent adding fields that can't tolerate races

The warned bitfields in struct scx_sched are updated racily from concurrent
CPUs causing RMW races, which is fine for these boolean warning flags. Add a
comment marking this area to prevent future fields that can't tolerate racy
updates from being added here.

Signed-off-by: Tejun Heo <tj@kernel.org>

Author: htejun

kernel/sched/ext_internal.h

@@ -895,6 +895,10 @@ struct scx_sched {
 	struct scx_dispatch_q	**global_dsqs;
 	struct scx_sched_pcpu __percpu *pcpu;
 
+	/*
+	 * Updates to the following warned bitfields can race causing RMW issues
+	 * but it doesn't really matter.
+	 */
 	bool			warned_zero_slice:1;
 	bool			warned_deprecated_rq:1;