regulator: Fix the logic to ensure new voltage setting in valid range

I think this is a typo.
To ensure new voltage setting won't greater than desc->max,
the equation should be desc->min + desc->step * new_val <= desc->max.
Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Cc: stable@vger.kernel.org

drivers/regulator/max8997.c

@@ -684,7 +684,7 @@ static int max8997_set_voltage_buck(struct regulator_dev *rdev,
 		}
 
 		new_val++;
-	} while (desc->min + desc->step + new_val <= desc->max);
+	} while (desc->min + desc->step * new_val <= desc->max);
 
 	new_idx = tmp_idx;
 	new_val = tmp_val;