zebra: evpn disable remove l2vni from l3vni list

zebra: evpn disable remove l2vni from l3vni list

Upon 'no advertise-all-vni', cleanup l2vni from
its tenant-vrf's l3vni list, instead of passed
zvrf->l3vni which will not be present in case
of default instance.

Reviewed By:
Testing Done:
Before Fix:
----------
TORC12(config-router-af)# advertise-all-vni
TORC12(config-router-af)# end
TORC12# show evpn vni 4001
VNI: 4001
  Type: L3
  Tenant VRF: vrf1
  Vxlan-Intf: vni4001
  State: Up
  Router MAC: 44:38:39:ff:ff:01
  L2 VNIs: 134217728 0 1000 1002 <-----

After Fix:
----------
TORC12# show evpn vni 4001
VNI: 4001
  Type: L3
  Tenant VRF: vrf1
  Vxlan-Intf: vni4001
  State: Up
  Router MAC: 44:38:39:ff:ff:01
  L2 VNIs: 1000 1002

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