net: dsa: microchip: remove dev_ops->setup() and teardown()

net: dsa: microchip: remove dev_ops->setup() and teardown()

All switch families have been converted to have their own
ds->ops->setup() methods and to call the common ksz_teardown().

Remove the no longer used ksz_setup() function and the associated
ksz_dev_ops callbacks.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Bastien Curutchet (Schneider Electric) <bastien.curutchet@bootlin.com>
Link: https://patch.msgid.link/20260521-clean-ksz-2nd-series-v3-5-75c38971c19a@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>