pinctrl: Make of_device_id array const

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

Signed-off-by: Kiran Padwal <kiran.padwal21@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/pinctrl/pinctrl-imx6q.c b/drivers/pinctrl/pinctrl-imx6q.c
index 8eb5ac1..59bb5b4 100644
--- a/drivers/pinctrl/pinctrl-imx6q.c
+++ b/drivers/pinctrl/pinctrl-imx6q.c
@@ -466,7 +466,7 @@
 	.npins = ARRAY_SIZE(imx6q_pinctrl_pads),
 };
 
-static struct of_device_id imx6q_pinctrl_of_match[] = {
+static const struct of_device_id imx6q_pinctrl_of_match[] = {
 	{ .compatible = "fsl,imx6q-iomuxc", },
 	{ /* sentinel */ }
 };