TCP IPv4-MAPPED IPv6 ADDRESSES

```
Description: The UDP implementation in net/udp contains support for Hybrid
dual-stack IPv6/IPv4 implementations that utilize a special
class of addresses, the IPv4-mapped IPv6 addresses. You can
see that UDP implementation in:

udp_callback.c:
ip6_map_ipv4addr(ipv4addr,
udp_send.c:
ip6_is_ipv4addr((FAR struct in6_addr*)conn->u.ipv6.raddr)))
ip6_is_ipv4addr((FAR struct in6_addr*)conn->u.ipv6.raddr))
in_addr_t raddr = ip6_get_ipv4addr((FAR struct in6_addr*)conn->u.ipv6.raddr);

There is no corresponding support for TCP sockets.
Status: Open
Priority: Low. I don't know of any issues now, but I am sure that
someone will encounter this in the future.
```