zebra: When displaying `show evpn arp-cache vni XX` add local and remote seq

zebra: When displaying `show evpn arp-cache vni XX` add local and remote seq

Add the local and remote sequence number to the `show evpn arp-cache vni XX` command.

VNI 1000111 #ARP (IPv4 and IPv6, local and remote) 15

IP                       Type   State    MAC               Remote VTEP           Seq #'s
fe80::202:ff:fe00:15     remote active   00:02:00:00:00:15 6.0.0.31              0/0
fe80::202:ff:fe00:8      local  active   00:02:00:00:00:08                       0/0
60.1.1.111               local  active   00:02:00:00:00:08                       0/0
2060:1:1:1::11           local  active   00:e0:ec:38:49:a1                       0/0
fe80::202:ff:fe00:11     remote active   00:02:00:00:00:11 6.0.0.30              0/0
2060:1:1:1::211          remote active   00:02:00:00:00:11 6.0.0.30              0/0
2060:1:1:1::121          remote active   00:02:00:00:00:0c 6.0.0.29              0/0
60.1.1.211               remote active   00:02:00:00:00:11 6.0.0.30              0/0
fe80::202:ff:fe00:c      remote active   00:02:00:00:00:0c 6.0.0.29              0/0
60.1.1.11                local  active   00:e0:ec:38:49:a1                       0/0
fe80::2e0:ecff:fe38:49a1 local  active   00:e0:ec:38:49:a1                       0/0
60.1.1.221               remote active   00:02:00:00:00:15 6.0.0.31              0/0
2060:1:1:1::111          local  active   00:02:00:00:00:08                       0/0
2060:1:1:1::221          remote active   00:02:00:00:00:15 6.0.0.31              0/0
60.1.1.121               remote active   00:02:00:00:00:0c 6.0.0.29              0/0

The seq numbers are at 0/0 because we have had no mobility events.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>