net: dsa: mv88e6xxx: enable .port_set_policy() for 6320 family

Commit f3a2cd32 ("net: dsa: mv88e6xxx: introduce .port_set_policy")
did not add the .port_set_policy() method for the 6320 family. Fix it.

Fixes: f3a2cd32 ("net: dsa: mv88e6xxx: introduce .port_set_policy")
Signed-off-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250317173250.28780-5-kabel@kernel.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>