net: punt bd->bi_ip_addr

This field gets read in one place (by "bdinfo"), and we can replace
that with getenv("ipaddr").  After all, the bi_ip_addr field is kept
up-to-date implicitly with the value of the ipaddr env var.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Reviewed-by: Joe Hershberger <joe.hershberger@ni.com>