clocksource/drivers/timer-ti-dm: Don't fail probe if int not found

Some timers may not have an interrupt routed to the A53 GIC, but the
timer PWM functionality can still be used by Linux Kernel. Therefore,
do not fail probe if interrupt is not found and ti,timer-pwm exists.

Signed-off-by: Judith Mendez <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Daniel Lezcano <[e-mail]>

drivers/clocksource/timer-ti-dm.c

···
 		return  -ENOMEM;
 
 	timer->irq = platform_get_irq(pdev, 0);
-	if (timer->irq < 0)
-		return timer->irq;
+	if (timer->irq < 0) {
+		if (of_property_read_bool(dev->of_node, "ti,timer-pwm"))
+			dev_info(dev, "Did not find timer interrupt, timer usable in PWM mode only\n");
+		else
+			return timer->irq;
+	}
 
 	timer->io_base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(timer->io_base))