net: dsa: mv88e6xxx: Remove OF check for IRQ domain

An IRQ domain will work without an OF node. It is not possible to
reference interrupts via a phandle, but C code can still use
irq_find_mapping() to get an interrupt from the domain.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx/global2.c

@@ -1047,9 +1047,6 @@ int mv88e6xxx_g2_irq_setup(struct mv88e6xxx_chip *chip)
 {
 	int err, irq, virq;
 
-	if (!chip->dev->of_node)
-		return -EINVAL;
-
 	chip->g2_irq.domain = irq_domain_add_simple(
 		chip->dev->of_node, 16, 0, &mv88e6xxx_g2_irq_domain_ops, chip);
 	if (!chip->g2_irq.domain)