This reverts commit 8bf8656d.

Reason for revert: Setting ovn-chassis-mac-mappings on network nodes 
is causing mac flooding [1] [2] for traffic between external ports, 
and very slow troughput in consequence.
OVN HA Chassis priorities between gateways should probably be managed
by Neutron [3]

[1] https://mail.openvswitch.org/pipermail/ovs-discuss/2020-September/050691.html
[2] https://mail.openvswitch.org/pipermail/ovs-discuss/2022-May/051837.html
[3] https://mail.openvswitch.org/pipermail/ovs-discuss/2022-October/052068.html

Change-Id: Ia3b279d7e2c08464fda1a5dc41518296f559e93f