mfd: stw481x: Check the return value of devm_regmap_init_i2c

devm_regmap_init_i2c can fail. Check for it.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/stw481x.c

@@ -186,6 +186,12 @@ static int stw481x_probe(struct i2c_client *client,
 	i2c_set_clientdata(client, stw481x);
 	stw481x->client = client;
 	stw481x->map = devm_regmap_init_i2c(client, &stw481x_regmap_config);
+	if (IS_ERR(stw481x->map)) {
+		ret = PTR_ERR(stw481x->map);
+		dev_err(&client->dev, "Failed to allocate register map: %d\n",
+			ret);
+		return ret;
+	}
 
 	ret = stw481x_startup(stw481x);
 	if (ret) {