regulator: vexpress: 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>
Acked-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/regulator/vexpress.c

@@ -123,7 +123,7 @@ static int vexpress_regulator_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static struct of_device_id vexpress_regulator_of_match[] = {
+static const struct of_device_id vexpress_regulator_of_match[] = {
 	{ .compatible = "arm,vexpress-volt", },
 	{ }
 };