regulator: max8973: Remove unused field from 'struct max8973_chip'

The 'struct regulator_dev *rdev' of 'struct max8973_chip' isn't used
anywhere in the driver so it can be removed safely.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/regulator/max8973-regulator.c

@@ -93,7 +93,6 @@
 struct max8973_chip {
 	struct device *dev;
 	struct regulator_desc desc;
-	struct regulator_dev *rdev;
 	struct regmap *regmap;
 	bool enable_external_control;
 	int dvs_gpio;
@@ -472,7 +471,6 @@ static int max8973_probe(struct i2c_client *client,
 		return ret;
 	}
 
-	max->rdev = rdev;
 	return 0;
 }