net: mscc: ocelot: don't refuse bonding interfaces we can't offload

Since switchdev/DSA exposes network interfaces that fulfill many of the
same user space expectations that dedicated NICs do, it makes sense to
not deny bonding interfaces with a bonding policy that we cannot offload,
but instead allow the bonding driver to select the egress interface in
software.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>