regulator: wm8400: Use DIV_ROUND_UP macro to calculate selector

Use DIV_ROUND_UP macro for better readability.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/regulator/wm8400-regulator.c

@@ -78,14 +78,14 @@ static int wm8400_ldo_set_voltage(struct regulator_dev *dev,
 
 	if (min_uV < 1700000) {
 		/* Steps of 50mV from 900mV;  */
-		val = (min_uV - 850001) / 50000;
+		val = DIV_ROUND_UP(min_uV - 900000, 50000);
 
 		if ((val * 50000) + 900000 > max_uV)
 			return -EINVAL;
 		BUG_ON((val * 50000) + 900000 < min_uV);
 	} else {
 		/* Steps of 100mV from 1700mV */
-		val = ((min_uV - 1600001) / 100000);
+		val = DIV_ROUND_UP(min_uV - 1700000, 100000);
 
 		if ((val * 100000) + 1700000 > max_uV)
 			return -EINVAL;
@@ -168,7 +168,7 @@ static int wm8400_dcdc_set_voltage(struct regulator_dev *dev,
 	if (min_uV < 850000)
 		return -EINVAL;
 
-	val = (min_uV - 825001) / 25000;
+	val = DIV_ROUND_UP(min_uV - 850000, 25000);
 
 	if (850000 + (25000 * val) > max_uV)
 		return -EINVAL;