regulator: palmas: Make of_device_id array const

Make of_device_id array const, because all OF functions
handle it as const.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/regulator/palmas-regulator.c

@@ -1199,7 +1199,7 @@ static int palmas_regulators_probe(struct platform_device *pdev)
 	return 0;
 }
 
-static struct of_device_id of_palmas_match_tbl[] = {
+static const struct of_device_id of_palmas_match_tbl[] = {
 	{ .compatible = "ti,palmas-pmic", },
 	{ .compatible = "ti,twl6035-pmic", },
 	{ .compatible = "ti,twl6036-pmic", },