[CUMULUS] bgpd: add evpn prefix in json output

PR 4850 has changed JSON output format where
evpn prefix is dissected to display each
fields. In effort to do so, it removed the
evpn prefix and prefixlen fields which causes
a regression issue in exisitng cli parser.
Adding back evpn prefix and prefixlen.

Ticket: CM-30105
Reviewed By:CCR-10420
Testing Done:

TORS1# show bgp l2vpn evpn route vni 1002 mac
00:02:00:00:00:01 ip fe80::202:ff:fe00:1 json
{
  "prefix":"[2]:[0]:[48]:[00:02:00:00:00:01]:[128]:[fe80::202:ff:fe00:1]",
  "prefixLen":352,
  "rd":"",
  "routeType":2,
  "ethTag":0,
  "macLen":48,
  "mac":"00:02:00:00:00:01",
  "ipLen":128,
  "ip":"fe80::202:ff:fe00:1",
  "paths":[
    [
      {
        "VNI":"1002\/4001",
        "aspath":{
...

Signed-off-by: Chirag Shah <[email protected]>

bgpd/bgp_route.c

@@ -11860,6 +11860,11 @@ void route_vty_out_detail_header(struct vty *vty, struct bgp *bgp,
 				    : "",
 				prd ? ":" : "", (struct prefix_evpn *)p);
 		} else {
+			char prefix_str[BUFSIZ];
+
+			prefix2str((const struct prefix_evpn *)p, prefix_str, sizeof(prefix_str));
+			json_object_string_add(json, "prefix", prefix_str);
+			json_object_int_add(json, "prefixLen", p->prefixlen);
 			json_object_string_add(
 				json, "rd",
 				prd ? prefix_rd2str(prd, buf1, sizeof(buf1),