regulator: max8997: Fix setting inappropriate value for ramp_delay variable

The ramp_delay variable can be set lower than the desired value.
This patch fixes it.

Signed-off-by: Donggeun Kim <dg77.kim@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: KyungMin Park <kyungmin.park@samsung.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

drivers/regulator/max8997.c

@@ -544,7 +544,8 @@ static int max8997_set_voltage_ldobuck(struct regulator_dev *rdev,
 			rid == MAX8997_BUCK4 || rid == MAX8997_BUCK5) {
 		/* If the voltage is increasing */
 		if (org < i)
-			udelay(desc->step * (i - org) / max8997->ramp_delay);
+			udelay(DIV_ROUND_UP(desc->step * (i - org),
+						max8997->ramp_delay));
 	}
 
 	return ret;