p2p: remove redundant discv5 dialer resource

[islishude]

It was added at 5fcc6e0

but since op-geth has merged the geth 1.15.x, this line is not necessary anymore

op-geth/eth/backend.go

Lines 499 to 503 in 28ddc5e

	// Add DHT nodes from discv5.
	if s.p2pServer.DiscoveryV5() != nil {
	filter := eth.NewNodeFilter(s.blockchain)
	iter := enode.Filter(s.p2pServer.DiscoveryV5().RandomNodes(), filter)
	s.discmix.AddSource(iter)

op-geth/p2p/server.go

Lines 500 to 505 in 28ddc5e

	for _, proto := range srv.Protocols {
	if proto.DialCandidates != nil && !added[proto.Name] {
	srv.discmix.AddSource(proto.DialCandidates)
	added[proto.Name] = true
	}
	}