regulator: Fix off-by-one value range checking for mc13xxx_regulator_get_voltage

We use val as array index,
thus the valid value rangae for val should be 0 .. n_voltages-1.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

drivers/regulator/mc13xxx-regulator-core.c

@@ -174,7 +174,7 @@ static int mc13xxx_regulator_get_voltage(struct regulator_dev *rdev)
 
 	dev_dbg(rdev_get_dev(rdev), "%s id: %d val: %d\n", __func__, id, val);
 
-	BUG_ON(val > mc13xxx_regulators[id].desc.n_voltages);
+	BUG_ON(val >= mc13xxx_regulators[id].desc.n_voltages);
 
 	return mc13xxx_regulators[id].voltages[val];
 }