bridge: fdb: support match on destination port in flush command

bridge: fdb: support match on destination port in flush command

Extend "fdb flush" command to match fdb entries with a specific destination
port.

Example:
$ bridge fdb flush dev vx10 port 1111
This will flush all fdb entries pointing to vx10 with destination port
1111.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: David Ahern <dsahern@kernel.org>