selftests: net: local_termination: parameterize test name

There are upcoming tests which verify the RX filtering of a bridge
(or bridge port), but under differing vlan_filtering conditions.
Since we currently print $h2 (the DUT) in the log_test() output, it
becomes necessary to make a further distinction between tests, to not
give the user the impression that the exact same thing is run twice.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>