perf: Simplify group_sched_out()

Since event_sched_out() clears cpuctx->exclusive upon removal of an
exclusive event (and only group leaders can be exclusive), there is no
point in group_sched_out() trying to do it too. It is impossible for
cpuctx->exclusive to still be set here.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201029162901.904060564@infradead.org

kernel/events/core.c

@@ -2312,9 +2312,6 @@ group_sched_out(struct perf_event *group_event,
 		event_sched_out(event, cpuctx, ctx);
 
 	perf_pmu_enable(ctx->pmu);
-
-	if (group_event->attr.exclusive)
-		cpuctx->exclusive = 0;
 }
 
 #define DETACH_GROUP	0x01UL