devlink: fix port new reply cmd type

Due to a c&p error, port new reply fills-up cmd with wrong value,
any other existing port command replies and notifications.

Fix it by filling cmd with value DEVLINK_CMD_PORT_NEW.

Skimmed through devlink userspace implementations, none of them cares
about this cmd value.

Reported-by: Chenyuan Yang <chenyuan0y@gmail.com>
Closes: https://lore.kernel.org/all/ZfZcDxGV3tSy4qsV@cy-server/


Fixes: cd76dcd6 ("devlink: Support add and delete devlink port")
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Link: https://lore.kernel.org/r/20240318091908.2736542-1-jiri@resnulli.us


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