cmd/utils: bump default maxpeers to 25

This should improve ethereum block propagation times since
we're not not broadcasting blocks to 100% of peers.

cmd/utils/flags.go

@@ -195,7 +195,7 @@ var (
 	MaxPeersFlag = cli.IntFlag{
 		Name:  "maxpeers",
 		Usage: "Maximum number of network peers (network disabled if set to 0)",
-		Value: 16,
+		Value: 25,
 	}
 	MaxPendingPeersFlag = cli.IntFlag{
 		Name:  "maxpendpeers",