clocksource/drivers/timer-atmel-pit: Remove uselesss WARN_ON_ONCE

IRQ handlers are running with IRQ disabled for a while, remove wrong
comment and useless test.
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

drivers/clocksource/timer-atmel-pit.c

@@ -149,12 +149,6 @@ static irqreturn_t at91sam926x_pit_interrupt(int irq, void *dev_id)
 {
 	struct pit_data *data = dev_id;
 
-	/*
-	 * irqs should be disabled here, but as the irq is shared they are only
-	 * guaranteed to be off if the timer irq is registered first.
-	 */
-	WARN_ON_ONCE(!irqs_disabled());
-
 	/* The PIT interrupt may be disabled, and is shared */
 	if (clockevent_state_periodic(&data->clkevt) &&
 	    (pit_read(data->base, AT91_PIT_SR) & AT91_PIT_PITS)) {