drm/xe: make heci_gsc_irq_chip const

The irq_chip definition can be const, make it so.
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240117122044.1544174-2-jani.nikula@intel.comSigned-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/xe/xe_heci_gsc.c

@@ -29,7 +29,7 @@ static void heci_gsc_irq_unmask(struct irq_data *d)
 	/* generic irq handling */
 }
 
-static struct irq_chip heci_gsc_irq_chip = {
+static const struct irq_chip heci_gsc_irq_chip = {
 	.name = "gsc_irq_chip",
 	.irq_mask = heci_gsc_irq_mask,
 	.irq_unmask = heci_gsc_irq_unmask,