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>

drivers/pinctrl/pinconf.c

@@ -670,7 +670,7 @@ static int pinconf_dbg_config_print(struct seq_file *s, void *d)
 	struct pinctrl_maps *maps_node;
 	struct pinctrl_map const *map;
 	struct pinctrl_dev *pctldev = NULL;
-	struct pinconf_ops *confops = NULL;
+	const struct pinconf_ops *confops = NULL;
 	int i, j;
 	bool found = false;