net: lan966x: Stop processing the MAC entry is port is wrong.

Currently when getting a new MAC is learn, the HW generates an
interrupt. So then the SW will check the new entry and checks if it
arrived on a correct port. If it didn't just generate a warning.
But this could still crash the system. Therefore stop processing that
entry when an issue is seen.

Fixes: 5ccd66e0

 ("net: lan966x: add support for interrupts from analyzer")
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>