zebra: set arp-nd-redirect when evpn-mh is enabled

Currently EVPN MH arp-nd-redirect is set when loopback
is enabled or advertise-all-vni is set.
This leads to unnecessary ARP/ND packets processing in FRR,
only enabled when EVPN MH is enabled means on first
local esi creation.

[upstream] This commit is dependent on other arp-nd-redirect
feature related commits.

Ticket:#3514816
Testing Done:

Post fix:

No local ESI
tor# show evpn es
Type: B bypass, L local, R remote, N non-DF
ESI                            Type ES-IF           VTEPs

arp-nd-redirect is disabled when EVPN MH is disabled
tor# show evpn arp-nd-redirect
EVPN ARP-reply/NA redirect: disabled
Stats:
  IPv4 ARP: 0

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

zebra/zebra_evpn_arp_nd.c

@@ -669,6 +669,9 @@ static void zebra_evpn_arp_nd_if_update_all(bool enable)
 /* ARP redirect for fast failover is enabled on the first local ES add */
 void zebra_evpn_arp_nd_failover_enable(void)
 {
+	if (!CHECK_FLAG(zmh_info->flags, ZEBRA_EVPN_MH_ENABLE))
+	    return;
+
 	/* If fast failover is not enabled there is nothing to do */
 	if (zmh_info->flags & ZEBRA_EVPN_MH_REDIRECT_OFF)
 		return;