irqchip/armada-370-xp: Do not allow mapping IRQ 0 and 1

IRQs 0 (IPI) and 1 (MSI) are handled internally by this driver,
generic_handle_domain_irq() is never called for these IRQs.

Disallow mapping these IRQs.

[ Marek: changed commit message ]
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>

drivers/irqchip/irq-armada-370-xp.c

@@ -560,6 +560,10 @@ static struct irq_chip armada_370_xp_irq_chip = {
 static int armada_370_xp_mpic_irq_map(struct irq_domain *h,
 				      unsigned int virq, irq_hw_number_t hw)
 {
+	/* IRQs 0 and 1 cannot be mapped, they are handled internally */
+	if (hw <= 1)
+		return -EINVAL;
+
 	armada_370_xp_irq_mask(irq_get_irq_data(virq));
 	if (!is_percpu_irq(hw))
 		writel(hw, per_cpu_int_base +