regulator: axp20x-regulator: constify regulator_ops structure

Declare regulator_ops structure as const as it is only stored in the ops
field of a regulator_desc structure. This field is of type const, so
regulator_ops structures having this property can be made const too.

File size before: drivers/regulator/axp20x-regulator.o
   text	   data	    bss	    dec	    hex	filename
  16848	   1232	      0	  18080	   46a0 regulator/axp20x-regulator.o

File size after: drivers/regulator/axp20x-regulator.o
   text	   data	    bss	    dec	    hex	filename
  17888	    192	      0	  18080	   46a0 regulator/axp20x-regulator.o

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/axp20x-regulator.c

@@ -128,11 +128,11 @@
 		.ops		= &axp20x_ops_range,				\
 	}
 
-static struct regulator_ops axp20x_ops_fixed = {
+static const struct regulator_ops axp20x_ops_fixed = {
 	.list_voltage		= regulator_list_voltage_linear,
 };
 
-static struct regulator_ops axp20x_ops_range = {
+static const struct regulator_ops axp20x_ops_range = {
 	.set_voltage_sel	= regulator_set_voltage_sel_regmap,
 	.get_voltage_sel	= regulator_get_voltage_sel_regmap,
 	.list_voltage		= regulator_list_voltage_linear_range,
@@ -141,7 +141,7 @@ static struct regulator_ops axp20x_ops_range = {
 	.is_enabled		= regulator_is_enabled_regmap,
 };
 
-static struct regulator_ops axp20x_ops = {
+static const struct regulator_ops axp20x_ops = {
 	.set_voltage_sel	= regulator_set_voltage_sel_regmap,
 	.get_voltage_sel	= regulator_get_voltage_sel_regmap,
 	.list_voltage		= regulator_list_voltage_linear,
@@ -150,7 +150,7 @@ static struct regulator_ops axp20x_ops = {
 	.is_enabled		= regulator_is_enabled_regmap,
 };
 
-static struct regulator_ops axp20x_ops_sw = {
+static const struct regulator_ops axp20x_ops_sw = {
 	.enable			= regulator_enable_regmap,
 	.disable		= regulator_disable_regmap,
 	.is_enabled		= regulator_is_enabled_regmap,