net: dsa: ocelot: seville: utilize of_mdiobus_register

net: dsa: ocelot: seville: utilize of_mdiobus_register

BugLink: https://bugs.launchpad.net/bugs/1964361
[ Upstream commit 5186c4a05b9713138b762a49467a8ab9753cdb36 ]

Switch seville to use of_mdiobus_register(bus, NULL) instead of just
mdiobus_register. This code is about to be pulled into a separate module
that can optionally define ports by the device_node.

Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>