tcp/dccp: Remove inet_connection_sock_af_ops.addr2sockaddr().

tcp/dccp: Remove inet_connection_sock_af_ops.addr2sockaddr().

inet_connection_sock_af_ops.addr2sockaddr() hasn't been used at all
in the git era.

  $ git grep addr2sockaddr $(git rev-list HEAD | tail -n 1)

Let's remove it.

Note that there was a 4 bytes hole after sockaddr_len and now it's
6 bytes, so the binary layout is not changed.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250318060112.3729-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>