regulator: ad5398: Use DIV_ROUND_UP macro to calculate selector

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/drivers/regulator/ad5398.c b/drivers/regulator/ad5398.c
index 483c809..26d23ad 100644
--- a/drivers/regulator/ad5398.c
+++ b/drivers/regulator/ad5398.c
@@ -94,8 +94,8 @@
 	if (max_uA > chip->max_uA || max_uA < chip->min_uA)
 		return -EINVAL;
 
-	selector = ((min_uA - chip->min_uA) * chip->current_level +
-			range_uA - 1) / range_uA;
+	selector = DIV_ROUND_UP((min_uA - chip->min_uA) * chip->current_level,
+				range_uA);
 	if (ad5398_calc_current(chip, selector) > max_uA)
 		return -EINVAL;