regulator: Ensure enough enable time for max8649

Integer division may truncate the result, thus max8649_enable_time() may return
slightly shorter enable time. This patch fixes it.
Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Acked-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NLiam Girdwood <lrg@slimlogic.co.uk>

drivers/regulator/max8649.c

@@ -221,7 +221,7 @@ static int max8649_enable_time(struct regulator_dev *rdev)
 	ret = (ret & MAX8649_RAMP_MASK) >> 5;
 	rate = (32 * 1000) >> ret;	/* uV/uS */
 
-	return (voltage / rate);
+	return DIV_ROUND_UP(voltage, rate);
 }
 
 static int max8649_set_mode(struct regulator_dev *rdev, unsigned int mode)