xtensa/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>
Reviewed-by: Max Filippov <jcmvbkbc@gmail.com>
Link: https://lore.kernel.org/r/20250520181644.2673067-16-kan.liang@linux.intel.com

Author: Kan Liang

arch/xtensa/kernel/perf_event.c

@@ -388,8 +388,7 @@ irqreturn_t xtensa_pmu_irq_handler(int irq, void *dev_id)
 			struct pt_regs *regs = get_irq_regs();
 
 			perf_sample_data_init(&data, 0, last_period);
-			if (perf_event_overflow(event, &data, regs))
-				xtensa_pmu_stop(event, 0);
+			perf_event_overflow(event, &data, regs);
 		}
 
 		rc = IRQ_HANDLED;