selftests: mirror_gre_lag_lacp: Drop unnecessary code

The selftest does not use functions from mirror_gre_lib, ditch the import.

It does not use arping either, so drop the require_command as well.
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/net/forwarding/mirror_gre_lag_lacp.sh

@@ -56,9 +56,6 @@ ALL_TESTS="
 NUM_NETIFS=6
 source lib.sh
 source mirror_lib.sh
-source mirror_gre_lib.sh
-
-require_command $ARPING
 
 vlan_host_create()
 {