net: dsa: microchip: remove IRQF_TRIGGER_FALLING in request_threaded_irq

KSZ swithes used interrupts for detecting the phy link up and down.
During registering the interrupt handler, it used IRQF_TRIGGER_FALLING
flag. But this flag has to be retrieved from device tree instead of hard
coding in the driver, so removing the flag.

Fixes: ff319a6 ("net: dsa: microchip: move interrupt handling logic from lan937x to ksz_common")
Reported-by: Christian Eggers <ceggers@arri.de>
Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Link: https://lore.kernel.org/r/20221213101440.24667-1-arun.ramadoss@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/dsa/microchip/ksz_common.c

@@ -1996,8 +1996,7 @@ static int ksz_irq_common_setup(struct ksz_device *dev, struct ksz_irq *kirq)
 		irq_create_mapping(kirq->domain, n);
 
 	ret = request_threaded_irq(kirq->irq_num, NULL, ksz_irq_thread_fn,
-				   IRQF_ONESHOT | IRQF_TRIGGER_FALLING,
-				   kirq->name, kirq);
+				   IRQF_ONESHOT, kirq->name, kirq);
 	if (ret)
 		goto out;