iio: Use an early return in iio_device_alloc to simplify code.

Noticed whilst reviewing Alexandru's patch to the same function.
If we simply flip the logic and return NULL immediately after memory
allocation failure we reduce the indent of the following block and
end up with more 'idiomatic' kernel code.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>

drivers/iio/industrialio-core.c

@@ -1510,27 +1510,27 @@ struct iio_dev *iio_device_alloc(int sizeof_priv)
 	alloc_size += IIO_ALIGN - 1;
 
 	dev = kzalloc(alloc_size, GFP_KERNEL);
+	if (!dev)
+		return NULL;
 
-	if (dev) {
-		dev->dev.groups = dev->groups;
-		dev->dev.type = &iio_device_type;
-		dev->dev.bus = &iio_bus_type;
-		device_initialize(&dev->dev);
-		dev_set_drvdata(&dev->dev, (void *)dev);
-		mutex_init(&dev->mlock);
-		mutex_init(&dev->info_exist_lock);
-		INIT_LIST_HEAD(&dev->channel_attr_list);
-
-		dev->id = ida_simple_get(&iio_ida, 0, 0, GFP_KERNEL);
-		if (dev->id < 0) {
-			/* cannot use a dev_err as the name isn't available */
-			pr_err("failed to get device id\n");
-			kfree(dev);
-			return NULL;
-		}
-		dev_set_name(&dev->dev, "iio:device%d", dev->id);
-		INIT_LIST_HEAD(&dev->buffer_list);
+	dev->dev.groups = dev->groups;
+	dev->dev.type = &iio_device_type;
+	dev->dev.bus = &iio_bus_type;
+	device_initialize(&dev->dev);
+	dev_set_drvdata(&dev->dev, (void *)dev);
+	mutex_init(&dev->mlock);
+	mutex_init(&dev->info_exist_lock);
+	INIT_LIST_HEAD(&dev->channel_attr_list);
+
+	dev->id = ida_simple_get(&iio_ida, 0, 0, GFP_KERNEL);
+	if (dev->id < 0) {
+		/* cannot use a dev_err as the name isn't available */
+		pr_err("failed to get device id\n");
+		kfree(dev);
+		return NULL;
 	}
+	dev_set_name(&dev->dev, "iio:device%d", dev->id);
+	INIT_LIST_HEAD(&dev->buffer_list);
 
 	return dev;
 }