net: dsa: mxl862xx: don't set user_mii_bus

The PHY addresses in the MII bus are not equal to the port addresses,
so the bus cannot be assigned as user_mii_bus. Falling back on the
user_mii_bus in case a PHY isn't declared in device tree will result in
using the wrong (in this case: off-by-+1) PHY.
Remove the wrong assignment.

Fixes: 23794be ("net: dsa: add basic initial driver for MxL862xx switches")
Suggested-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://patch.msgid.link/0f0df310fd8cab57e0e5e3d0831dd057fd05bcd5.1773103271.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: dangowrt

drivers/net/dsa/mxl862xx/mxl862xx.c

@@ -149,7 +149,6 @@ static int mxl862xx_setup_mdio(struct dsa_switch *ds)
 		return -ENOMEM;
 
 	bus->priv = priv;
-	ds->user_mii_bus = bus;
 	bus->name = KBUILD_MODNAME "-mii";
 	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(dev));
 	bus->read_c45 = mxl862xx_phy_read_c45_mii_bus;