This is always a duplicate of the "control" field. It causes
confusion wrt intf_data updates and cleanups.

Cc: Alexey Orishko <alexey.orishko@gmail.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>