net: dsa: ocelot: use devres in seville_probe()

Russell King suggested that felix_vsc9959, seville_vsc9953 and
ocelot_ext have a large portion of duplicated init and teardown code,
which could be made common [1]. The teardown code could even be
simplified away if we made use of devres, something which is used here
and there in the felix driver, just not very consistently.

[1] https://lore.kernel.org/all/Zh1GvcOTXqb7CpQt@shell.armlinux.org.uk/

Prepare the ground in the seville_vsc9953 driver, by allocating the data
structures using devres and deleting the kfree() calls. This also
deletes the "Failed to allocate ..." message, since memory allocation
errors are extremely loud anyway, and it's hard to miss them.
Suggested-by: "Russell King (Oracle)" <linux@armlinux.org.uk>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/ocelot/seville_vsc9953.c

@@ -971,42 +971,36 @@ static const struct felix_info seville_info_vsc9953 = {
 
 static int seville_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
 	struct dsa_switch *ds;
 	struct ocelot *ocelot;
 	struct resource *res;
 	struct felix *felix;
 	int err;
 
-	felix = kzalloc(sizeof(struct felix), GFP_KERNEL);
-	if (!felix) {
-		err = -ENOMEM;
-		dev_err(&pdev->dev, "Failed to allocate driver memory\n");
-		goto err_alloc_felix;
-	}
+	felix = devm_kzalloc(dev, sizeof(struct felix), GFP_KERNEL);
+	if (!felix)
+		return -ENOMEM;
 
 	platform_set_drvdata(pdev, felix);
 
 	ocelot = &felix->ocelot;
-	ocelot->dev = &pdev->dev;
+	ocelot->dev = dev;
 	ocelot->num_flooding_pgids = 1;
 	felix->info = &seville_info_vsc9953;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res) {
-		err = -EINVAL;
-		dev_err(&pdev->dev, "Invalid resource\n");
-		goto err_alloc_felix;
+		dev_err(dev, "Invalid resource\n");
+		return -EINVAL;
 	}
 	felix->switch_base = res->start;
 
-	ds = kzalloc(sizeof(struct dsa_switch), GFP_KERNEL);
-	if (!ds) {
-		err = -ENOMEM;
-		dev_err(&pdev->dev, "Failed to allocate DSA switch\n");
-		goto err_alloc_ds;
-	}
+	ds = devm_kzalloc(dev, sizeof(struct dsa_switch), GFP_KERNEL);
+	if (!ds)
+		return -ENOMEM;
 
-	ds->dev = &pdev->dev;
+	ds->dev = dev;
 	ds->num_ports = felix->info->num_ports;
 	ds->ops = &felix_switch_ops;
 	ds->phylink_mac_ops = &felix_phylink_mac_ops;
@@ -1015,18 +1009,9 @@ static int seville_probe(struct platform_device *pdev)
 	felix->tag_proto = DSA_TAG_PROTO_SEVILLE;
 
 	err = dsa_register_switch(ds);
-	if (err) {
-		dev_err(&pdev->dev, "Failed to register DSA switch: %d\n", err);
-		goto err_register_ds;
-	}
+	if (err)
+		dev_err(dev, "Failed to register DSA switch: %d\n", err);
 
-	return 0;
-
-err_register_ds:
-	kfree(ds);
-err_alloc_ds:
-err_alloc_felix:
-	kfree(felix);
 	return err;
 }
 
@@ -1038,9 +1023,6 @@ static void seville_remove(struct platform_device *pdev)
 		return;
 
 	dsa_unregister_switch(felix->ds);
-
-	kfree(felix->ds);
-	kfree(felix);
 }
 
 static void seville_shutdown(struct platform_device *pdev)