hsr: ratelimit only when errors are printed

Recently, when automatically merging -net and net-next in MPTCP devel
tree, our CI reported [1] a conflict in hsr, the same as the one
reported by Stephen in netdev [2].

When looking at the conflict, I noticed it is in fact the v1 [3] that
has been applied in -net and the v2 [4] in net-next. Maybe the v1 was
applied by accident.

As mentioned by Jakub Kicinski [5], the new condition makes more sense
before the net_ratelimit(), not to update net_ratelimit's state which is
unnecessary if we're not going to print either way.

Here, this modification applies the v2 but in -net.

Link: https://github.com/multipath-tcp/mptcp_net-next/actions/runs/4423171069 [1]
Link: https://lore.kernel.org/netdev/20230315100914.53fc1760@canb.auug.org.au/ [2]
Link: https://lore.kernel.org/netdev/20230307133229.127442-1-koverskeid@gmail.com/ [3]
Link: https://lore.kernel.org/netdev/20230309092302.179586-1-koverskeid@gmail.com/ [4]
Link: https://lore.kernel.org/netdev/20230308232001.2fb62013@kernel.org/

 [5]
Fixes: 28e8cabe ("net: hsr: Don't log netdev_err message on unknown prp dst node")
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Reviewed-by: Steen Hegelund <Steen.Hegelund@microchip.com>
Link: https://lore.kernel.org/r/20230315-net-20230315-hsr_framereg-ratelimit-v1-1-61d2ef176d11@tessares.net


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