irq_domain/c6x: constify irq_domain structures

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Mark Salter <msalter@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/c6x/platforms/megamod-pic.c b/arch/c6x/platforms/megamod-pic.c
index 61f5863..9f35fbf 100644
--- a/arch/c6x/platforms/megamod-pic.c
+++ b/arch/c6x/platforms/megamod-pic.c
@@ -148,7 +148,7 @@
 	return 0;
 }
 
-static struct irq_domain_ops megamod_domain_ops = {
+static const struct irq_domain_ops megamod_domain_ops = {
 	.map	= megamod_map,
 	.xlate	= megamod_xlate,
 };