pinctrl: constify of_device_id array

of_device_id is always used as const.
(See driver.of_match_table and open firmware functions)

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Patrice Chotard <patrice.chotard@st.com>
Acked-by: Maxime Coquelin <maxime.coquelin@st.com>
Acked-by: Hongzhou Yang <hongzhou.yang@mediatek.com>
Acked-by: Lee Jones <lee@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/pinctrl/sunxi/pinctrl-sun5i-a13.c b/drivers/pinctrl/sunxi/pinctrl-sun5i-a13.c
index 4bd2347..2bb07b3 100644
--- a/drivers/pinctrl/sunxi/pinctrl-sun5i-a13.c
+++ b/drivers/pinctrl/sunxi/pinctrl-sun5i-a13.c
@@ -388,7 +388,7 @@
 				  &sun5i_a13_pinctrl_data);
 }
 
-static struct of_device_id sun5i_a13_pinctrl_match[] = {
+static const struct of_device_id sun5i_a13_pinctrl_match[] = {
 	{ .compatible = "allwinner,sun5i-a13-pinctrl", },
 	{}
 };