nfp: bpf: allocate vNIC priv for keeping track of the offloaded program

After TC offloads were converted to callbacks we have no choice
but keep track of the offloaded filter in the driver.

Since this change came a little late in the release cycle
there were a number of conflicts and allocation of vNIC priv
structure seems to have slipped away in linux-next.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>