net: lan966x: Fix usage of lan966x->mac_lock when used by FDB

net: lan966x: Fix usage of lan966x->mac_lock when used by FDB

When the SW bridge was trying to add/remove entries to/from HW, the
access to HW was not protected by any lock. In this way, it was
possible to have race conditions.
Fix this by using the lan966x->mac_lock to protect parallel access to HW
for this cases.

Fixes: 25ee9561ec622 ("net: lan966x: More MAC table functionality")
Signed-off-by: Horatiu Vultur <[email protected]>
Reviewed-by: Vladimir Oltean <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>