MIPS: pci-ar2315: Constify static irq_domain_ops

The only usage of ar2315_pci_irq_domain_ops is to pass its address to
irq_domain_add_linear() which takes a pointer to const struct
irq_domain_ops. Make it const to allow the compiler to put it in
read-only memory.
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/pci/pci-ar2315.c

@@ -384,7 +384,7 @@ static int ar2315_pci_irq_map(struct irq_domain *d, unsigned irq,
 	return 0;
 }
 
-static struct irq_domain_ops ar2315_pci_irq_domain_ops = {
+static const struct irq_domain_ops ar2315_pci_irq_domain_ops = {
 	.map = ar2315_pci_irq_map,
 };