pinctrl: Declare operation structures as const

The pinconf, pinctrl and pinmux operation structures hold function
pointers that are never modified. Declare them as const.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/pinctrl/devicetree.c b/drivers/pinctrl/devicetree.c
index fd40a11..c7b7cb4 100644
--- a/drivers/pinctrl/devicetree.c
+++ b/drivers/pinctrl/devicetree.c
@@ -41,7 +41,7 @@
 		     struct pinctrl_map *map, unsigned num_maps)
 {
 	if (pctldev) {
-		struct pinctrl_ops *ops = pctldev->desc->pctlops;
+		const struct pinctrl_ops *ops = pctldev->desc->pctlops;
 		ops->dt_free_map(pctldev, map, num_maps);
 	} else {
 		/* There is no pctldev for PIN_MAP_TYPE_DUMMY_STATE */
@@ -122,7 +122,7 @@
 {
 	struct device_node *np_pctldev;
 	struct pinctrl_dev *pctldev;
-	struct pinctrl_ops *ops;
+	const struct pinctrl_ops *ops;
 	int ret;
 	struct pinctrl_map *map;
 	unsigned num_maps;