mfd: max8997: Enforce mfd_add_devices() return value check

The original author provided a random return value check which is
redundant and seemingly floating. This patch not only relocates
the check so it is more clearly associated with the invokation of
mfd_add_devices(), but provides a store for the error value. We
also print a meaningful message on error before returning.
Signed-off-by: Laszlo Papp <lpapp@kde.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/max8997.c

@@ -228,18 +228,19 @@ static int max8997_i2c_probe(struct i2c_client *i2c,
 
 	max8997_irq_init(max8997);
 
-	mfd_add_devices(max8997->dev, -1, max8997_devs,
+	ret = mfd_add_devices(max8997->dev, -1, max8997_devs,
 			ARRAY_SIZE(max8997_devs),
 			NULL, 0, NULL);
+	if (ret < 0) {
+		dev_err(max8997->dev, "failed to add MFD devices %d\n", ret);
+		goto err_mfd;
+	}
 
 	/*
 	 * TODO: enable others (flash, muic, rtc, battery, ...) and
 	 * check the return value
 	 */
 
-	if (ret < 0)
-		goto err_mfd;
-
 	/* MAX8997 has a power button input. */
 	device_init_wakeup(max8997->dev, pdata->wakeup);