ndo_fdb_del: Add a parameter to report whether notification was sent

In a similar fashion to ndo_fdb_add, which was covered in the previous
patch, add the bool *notified argument to ndo_fdb_del. Callees that send a
notification on their own set the flag to true.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/06b1acf4953ef0a5ed153ef1f32d7292044f2be6.1731589511.git.petrm@nvidia.com


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