of: irq: Remove WARN_ON() for kzalloc() failure

There is no need to print a backtrace if kzalloc() fails, as the memory
allocation core already takes care of that.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rob Herring <robh@kernel.org>

drivers/of/irq.c

@@ -500,7 +500,7 @@ void __init of_irq_init(const struct of_device_id *matches)
 		 * pointer, interrupt-parent device_node etc.
 		 */
 		desc = kzalloc(sizeof(*desc), GFP_KERNEL);
-		if (WARN_ON(!desc)) {
+		if (!desc) {
 			of_node_put(np);
 			goto err;
 		}