max17042_battery: Use devm_kzalloc() where applicable

This allows us to simplify probe and exit function.

Signed-off-by: Karol Lewandowski <k.lewandowsk@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
diff --git a/drivers/power/max17042_battery.c b/drivers/power/max17042_battery.c
index bd88deb..872e9b4 100644
--- a/drivers/power/max17042_battery.c
+++ b/drivers/power/max17042_battery.c
@@ -619,7 +619,7 @@
 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
 		return -EIO;
 
-	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
 	if (!chip)
 		return -ENOMEM;
 
@@ -676,10 +676,8 @@
 	}
 
 	ret = power_supply_register(&client->dev, &chip->battery);
-	if (ret) {
+	if (ret)
 		dev_err(&client->dev, "failed: power supply register\n");
-		kfree(chip);
-	}
 	return ret;
 }
 
@@ -688,7 +686,6 @@
 	struct max17042_chip *chip = i2c_get_clientdata(client);
 
 	power_supply_unregister(&chip->battery);
-	kfree(chip);
 	return 0;
 }