mtd: orion_nand: Make of_device_id array const

Make of_device_id array const, because all OF functions
handle it as const.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/nand/orion_nand.c

@@ -214,7 +214,7 @@ static int orion_nand_remove(struct platform_device *pdev)
 }
 
 #ifdef CONFIG_OF
-static struct of_device_id orion_nand_of_match_table[] = {
+static const struct of_device_id orion_nand_of_match_table[] = {
 	{ .compatible = "marvell,orion-nand", },
 	{},
 };