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/pinctrl-lantiq.c b/drivers/pinctrl/pinctrl-lantiq.c
index a703846..615c500 100644
--- a/drivers/pinctrl/pinctrl-lantiq.c
+++ b/drivers/pinctrl/pinctrl-lantiq.c
@@ -169,7 +169,7 @@
 	return 0;
 }
 
-static struct pinctrl_ops ltq_pctrl_ops = {
+static const struct pinctrl_ops ltq_pctrl_ops = {
 	.get_groups_count	= ltq_get_group_count,
 	.get_group_name		= ltq_get_group_name,
 	.get_group_pins		= ltq_get_group_pins,
@@ -311,7 +311,7 @@
 	return info->apply_mux(pctrldev, mfp, pin_func);
 }
 
-static struct pinmux_ops ltq_pmx_ops = {
+static const struct pinmux_ops ltq_pmx_ops = {
 	.get_functions_count	= ltq_pmx_func_count,
 	.get_function_name	= ltq_pmx_func_name,
 	.get_function_groups	= ltq_pmx_get_groups,