net: mscc: ocelot: delete ocelot_port :: xmit_template

This is no longer used since commit 7c4bb540 ("net: dsa: tag_ocelot:
create separate tagger for Seville").

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>