net: dsa: bcm_sf2: Fix a possible memory leak in bcm_sf2_mdio_register()

bcm_sf2_mdio_register() calls of_phy_find_device() and then
phy_device_remove() in a loop to remove existing PHY devices.
of_phy_find_device() eventually calls bus_find_device(), which calls
get_device() on the returned struct device * to increment the refcount.
The current implementation does not decrement the refcount, which causes
memory leak.

This commit adds the missing phy_device_free() call to decrement the
refcount via put_device() to balance the refcount.

Fixes: 771089c ("net: dsa: bcm_sf2: Ensure that MDIO diversion is used")
Signed-off-by: Joe Hattori <[email protected]>
Tested-by: Florian Fainelli <[email protected]>
Reviewed-by: Florian Fainelli <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

drivers/net/dsa/bcm_sf2.c

@@ -675,8 +675,10 @@ static int bcm_sf2_mdio_register(struct dsa_switch *ds)
 			of_remove_property(child, prop);
 
 		phydev = of_phy_find_device(child);
-		if (phydev)
+		if (phydev) {
 			phy_device_remove(phydev);
+			phy_device_free(phydev);
+		}
 	}
 
 	err = mdiobus_register(priv->user_mii_bus);