selftests: forwarding: Do not configure nexthop objects twice

routing_nh_obj() is used to configure the nexthop objects employed by
the test, but it is called twice resulting in "RTNETLINK answers: File
exists" messages.

Remove the first call, so that the function is only called after
setup_wait(), when all the interfaces are up and ready.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -312,7 +312,6 @@ setup_prepare()
 
 	router1_create
 	router2_create
-	routing_nh_obj
 
 	forwarding_enable
 }