zebra: fix dup addr detect remote macip add case

zebra: fix dup addr detect remote macip add case

A MACIP is detected as duplicate and after that
the host continue to move behind different VTEPs results
in local VTEP receiving remote mobility events.
In remote_macip_add, ensure to trigger dad if
MAC is marked as duplicate. In case of freeze
action enabled, is_dup_detect will be set to
avoids installing frozen MAC into kernel.

Ticket:CM-23649
Testing Done:
Configured detection action freeze with detection count
as 7 at DUT and >7 at remote VTEP,
trigger MAC-IP mobility between VTEPs.
once tdetection count reached, MAC detected as duplicate,
post detection move the host to remote. The local VTEP
receives remote macip add and entry is not installed into
kernel with fix.

root@VTEP1:~# net show evpn mac vni 1002 mac aa:aa:aa:aa:aa:aa
MAC: aa:aa:aa:aa:aa:aa
Remote VTEP: 27.0.0.16
Local Seq: 7 Remote Seq: 8
Duplicate, detected at Fri Jan 25 05:03:29 2019
Neighbors:
11.11.11.11 Inactive

Kernel entry still points to LOCAL
root@VTEP1:~# bridge fdb show | grep aa:aa:aa
aa:aa:aa:aa:aa:aa dev hostbond3 vlan 1002 master VxLanA-1

Signed-off-by: Chirag Shah <chirag@cumulusnetworks.com>