net: dsa: hellcreek: Print warning only once

[ Upstream commit 52267ce2 ]

In case the source port cannot be decoded, print the warning only once. This
still brings attention to the user and does not spam the logs at the same time.

Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20220830163448.8921-1-kurt@linutronix.de


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