forcedeath: Fix bql support for forcedeath

Moved netdev_completed_queue() out of while loop in function nv_tx_done_optimized().
Because this function was in while loop,
BUG_ON(count > dql->num_queued - dql->num_completed)
was hit in dql_completed().

Signed-off-by: Igor Maravic <igorm@etf.rs>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>