Merge pull request #16587 from opensourcerouting/fix/revert_ipv4_mapped_ipv6_stuff_10.1

Revert IPv4 mapped IPv6 stuff for 10.1

diff --cc bgpd/bgp_nht.c
Simple merge

diff --cc bgpd/bgp_route.c
Simple merge

diff --cc bgpd/bgp_updgrp_packet.c
Simple merge

diff --cc bgpd/bgp_zebra.c
Simple merge