ipc: freebsd: use AF_LOCAL for the control socket

ipc: freebsd: use AF_LOCAL for the control socket

AF_INET assumes that IPv4 is built into the kernel, but it's completely
valid to build a kernel without it.  unix(4) sockets, on the other hand,
are not-optional in the kernel build.  Given that interface ioctls can
be invoked on any kind of socket, switch to the safer one to avoid
breaking on IPv6-only kernels.

Signed-off-by: Kyle Evans <kevans@FreeBSD.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>