net: ethernet: xilinx: Do not use NO_IRQ in axienet

This driver is used on Microblaze and will be used
on Arm Zynq.
Microblaze doesn't define NO_IRQ and no IRQ is 0.
Arm still uses NO_IRQ as -1 and there is no option
to connect IRQ to irq 0.

That's why <= 0 is only one option how to find out
undefined IRQ.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/xilinx/xilinx_axienet_main.c

@@ -1590,7 +1590,7 @@ static int axienet_of_probe(struct platform_device *op)
 	lp->rx_irq = irq_of_parse_and_map(np, 1);
 	lp->tx_irq = irq_of_parse_and_map(np, 0);
 	of_node_put(np);
-	if ((lp->rx_irq == NO_IRQ) || (lp->tx_irq == NO_IRQ)) {
+	if ((lp->rx_irq <= 0) || (lp->tx_irq <= 0)) {
 		dev_err(&op->dev, "could not determine irqs\n");
 		ret = -ENOMEM;
 		goto err_iounmap_2;