irqchip/gic-v2m: Add const to of_device_id

struct of_device_id should normally be const.
Signed-off-by: Xiang wangx <wangxiang@cdjrlc.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211209132453.25623-1-wangxiang@cdjrlc.com

drivers/irqchip/irq-gic-v2m.c

@@ -405,7 +405,7 @@ static int __init gicv2m_init_one(struct fwnode_handle *fwnode,
 	return ret;
 }
 
-static struct of_device_id gicv2m_device_id[] = {
+static const struct of_device_id gicv2m_device_id[] = {
 	{	.compatible	= "arm,gic-v2m-frame",	},
 	{},
 };