gpio: octeon: Constify octeon_gpio_match table

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-octeon.c

@@ -116,7 +116,7 @@ static int octeon_gpio_probe(struct platform_device *pdev)
 	return 0;
 }
 
-static struct of_device_id octeon_gpio_match[] = {
+static const struct of_device_id octeon_gpio_match[] = {
 	{
 		.compatible = "cavium,octeon-3860-gpio",
 	},