be2net: Fix CSO for UDP packets

We're setting skb->ip_summed to CHECKSUM_NONE for all non-TCP pkts, making the stack
recompute checksum.This is a bug for UDP pkts for which cso must be used.

Signed-off-by: Somnath Kotur <somnath.kotur@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>