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-at91.c b/drivers/pinctrl/pinctrl-at91.c
index 75933a6..e50fa5f 100644
--- a/drivers/pinctrl/pinctrl-at91.c
+++ b/drivers/pinctrl/pinctrl-at91.c
@@ -294,7 +294,7 @@
 {
 }
 
-static struct pinctrl_ops at91_pctrl_ops = {
+static const struct pinctrl_ops at91_pctrl_ops = {
 	.get_groups_count	= at91_get_groups_count,
 	.get_group_name		= at91_get_group_name,
 	.get_group_pins		= at91_get_group_pins,
@@ -696,7 +696,7 @@
 	/* Set the pin to some default state, GPIO is usually default */
 }
 
-static struct pinmux_ops at91_pmx_ops = {
+static const struct pinmux_ops at91_pmx_ops = {
 	.get_functions_count	= at91_pmx_get_funcs_count,
 	.get_function_name	= at91_pmx_get_func_name,
 	.get_function_groups	= at91_pmx_get_groups,
@@ -776,7 +776,7 @@
 {
 }
 
-static struct pinconf_ops at91_pinconf_ops = {
+static const struct pinconf_ops at91_pinconf_ops = {
 	.pin_config_get			= at91_pinconf_get,
 	.pin_config_set			= at91_pinconf_set,
 	.pin_config_dbg_show		= at91_pinconf_dbg_show,