bridge: vlan: flush the dynamically learned entries on port vlan delete

Add a new argument to br_fdb_delete_by_port which allows to specify a
vid to match when flushing entries and use it in nbp_vlan_delete() to
flush the dynamically learned entries of the vlan/port pair when removing
a vlan from a port. Before this patch only the local mac was being
removed and the dynamically learned ones were left to expire.
Note that the do_all argument is still respected and if specified, the
vid will be ignored.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>