net: ag71xx: get reset control using devm api

Currently, the of variant is missing reset_control_put in error paths.
The devm variant does not require it.

Allows removing mdio_reset from the struct as it is not used outside the
function.
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://patch.msgid.link/20240905194938.8453-6-rosenp@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/atheros/ag71xx.c

@@ -379,7 +379,6 @@ struct ag71xx {
 	u32 fifodata[3];
 	int mac_idx;
 
-	struct reset_control *mdio_reset;
 	struct clk *clk_mdio;
 };
 
@@ -689,6 +688,7 @@ static int ag71xx_mdio_probe(struct ag71xx *ag)
 {
 	struct device *dev = &ag->pdev->dev;
 	struct net_device *ndev = ag->ndev;
+	struct reset_control *mdio_reset;
 	static struct mii_bus *mii_bus;
 	struct device_node *np, *mnp;
 	int err;
@@ -705,10 +705,10 @@ static int ag71xx_mdio_probe(struct ag71xx *ag)
 	if (!mii_bus)
 		return -ENOMEM;
 
-	ag->mdio_reset = of_reset_control_get_exclusive(np, "mdio");
-	if (IS_ERR(ag->mdio_reset)) {
+	mdio_reset = devm_reset_control_get_exclusive(dev, "mdio");
+	if (IS_ERR(mdio_reset)) {
 		netif_err(ag, probe, ndev, "Failed to get reset mdio.\n");
-		return PTR_ERR(ag->mdio_reset);
+		return PTR_ERR(mdio_reset);
 	}
 
 	mii_bus->name = "ag71xx_mdio";
@@ -719,10 +719,10 @@ static int ag71xx_mdio_probe(struct ag71xx *ag)
 	mii_bus->parent = dev;
 	snprintf(mii_bus->id, MII_BUS_ID_SIZE, "%s.%d", np->name, ag->mac_idx);
 
-	if (!IS_ERR(ag->mdio_reset)) {
-		reset_control_assert(ag->mdio_reset);
+	if (!IS_ERR(mdio_reset)) {
+		reset_control_assert(mdio_reset);
 		msleep(100);
-		reset_control_deassert(ag->mdio_reset);
+		reset_control_deassert(mdio_reset);
 		msleep(200);
 	}