selftests: mirror_gre_bridge_1q_lag: Enslave port to bridge before other configurations

Using mlxsw driver, the configurations are offloaded just in case that
there is a physical port which is enslaved to the virtual device
(e.g., to a bridge). In 'mirror_gre_bridge_1q_lag' test, the bridge gets an
address and route before there are ports in the bridge. It means that these
configurations are not offloaded.

Till now the test passes with mlxsw driver even that the RIF of the
bridge is not in the hardware, because the ARP packets are trapped in
layer 2 and also mirrored, so there is no real need of the RIF in hardware.
The previous patch changed the traps 'ARP_REQUEST' and 'ARP_RESPONSE' to
be done at layer 3 instead of layer 2. With this change the ARP packets are
not trapped during the test, as the RIF is not in the hardware because of
the order of configurations.

Reorder the configurations to make them to be offloaded, then the test will
pass with the change of the traps.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>