devlink: bring port new reply back

In the offending fixes commit I mistakenly removed the reply message of
the port new command. I was under impression it is a new port
notification, partly due to the "notify" in the name of the helper
function. Bring the code sending reply with new port message back, this
time putting it directly to devlink_nl_cmd_port_new_doit()

Fixes: c496daeb ("devlink: remove duplicate port notification")
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20230531142025.2605001-1-jiri@resnulli.us


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