netlink/route: Support modifying IFLA_ADDRESS with RTM_NEWLINK
Allows setting link-layer address (MAC) by specifying the IFLA_ADDRESS
attribute on RTM_NEWLINK requests.
Reviewed by: melifaro, obiwac, mckusick (mentor)
Approved by: melifaro, obiwac, mckusick (mentor)
Sponsored by: Google LLC (GSoC)
Differential Revision: https://reviews.freebsd.org/D51922