drm/msm: constify irq_domain_ops

struct irq_domain_ops is not modified, so it can be made const.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/mdp/mdp5/mdp5_mdss.c

@@ -116,7 +116,7 @@ static int mdss_hw_irqdomain_map(struct irq_domain *d, unsigned int irq,
 	return 0;
 }
 
-static struct irq_domain_ops mdss_hw_irqdomain_ops = {
+static const struct irq_domain_ops mdss_hw_irqdomain_ops = {
 	.map = mdss_hw_irqdomain_map,
 	.xlate = irq_domain_xlate_onecell,
 };