arc/perf: Remove driver-specific throttle support

The throttle support has been added in the generic code. Remove
the driver-specific throttle support.

Besides the throttle, perf_event_overflow may return true because of
event_limit. It already does an inatomic event disable. The pmu->stop
is not required either.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Vineet Gupta <vgupta@kernel.org>
Link: https://lore.kernel.org/r/20250520181644.2673067-12-kan.liang@linux.intel.com

Author: Kan Liang

arch/arc/kernel/perf_event.c

@@ -599,10 +599,8 @@ static irqreturn_t arc_pmu_intr(int irq, void *dev)
 
 		arc_perf_event_update(event, &event->hw, event->hw.idx);
 		perf_sample_data_init(&data, 0, hwc->last_period);
-		if (arc_pmu_event_set_period(event)) {
-			if (perf_event_overflow(event, &data, regs))
-				arc_pmu_stop(event, 0);
-		}
+		if (arc_pmu_event_set_period(event))
+			perf_event_overflow(event, &data, regs);
 
 		active_ints &= ~BIT(idx);
 	} while (active_ints);