Rename the last remaining bits depending on linux/netdevice.h to
ifnet and related functions. This makes mlx5 no longer depend on
linux/netdevice.h (though it indirectly still includes the header
through an ofed header for now so I hope I haven't missed any)
and helps clearing up linux/netdevice.h.
Sponsored-by: The FreeBSD Foundation
MFC-after: 2 weeks
Reviewed-by: ...
Differential Revision: