sky2: use napi_complete_done

Update the sky2 driver to pass number of packets done to NAPI.
The driver was never updated when napi_complete_done was added.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>