mfd: 88pm860x: Fix I2C device resource leak on regmap init fail

During probe the driver allocates dummy I2C device for companion chip
and then allocates a regmap for it. If regmap_init_i2c() fails then the
I2C driver (allocated with i2c_new_dummy()) is not freed and this
resource leaks.

Cc: stable@vger.kernel.org
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/88pm860x-core.c

@@ -1185,6 +1185,7 @@ static int pm860x_probe(struct i2c_client *client,
 			ret = PTR_ERR(chip->regmap_companion);
 			dev_err(&chip->companion->dev,
 				"Failed to allocate register map: %d\n", ret);
+			i2c_unregister_device(chip->companion);
 			return ret;
 		}
 		i2c_set_clientdata(chip->companion, chip);