cmd/gobgp: fix parseEvpnEthernetAutoDiscoveryArgs

esi-label follows the format:
   [esi-label <esi-label> [single-active | all-active]]

extractReserved() splits by spaces, returning a list for esi-label, hence
failing the type check.

Change its parameter value type to paramList to be able to accomodate cases
such as "... esi-label 400 single-active".

cmd/gobgp/global.go

@@ -470,7 +470,7 @@ func parseEvpnEthernetAutoDiscoveryArgs(args []string) (bgp.AddrPrefixInterface,
 		"rd":        paramSingle,
 		"rt":        paramList,
 		"encap":     paramSingle,
-		"esi-label": paramSingle})
+		"esi-label": paramList})
 	if err != nil {
 		return nil, nil, err
 	}