drivers/net/oki-semi: Donot recompute IP header checksum

If I understand correct, NETIF_F_IP_CSUM only means the hardware
will compute the TCP/UDP checksum, IP checksum is always computed
in software

So as a workround of hardware unable to compute small packages
checksum, do not need to compute IP header checksum.
Signed-off-by: NRongQing.Li <roy.qing.li@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c

@@ -1240,8 +1240,6 @@ static void pch_gbe_tx_queue(struct pch_gbe_adapter *adapter,
 		if (skb->protocol == htons(ETH_P_IP)) {
 			struct iphdr *iph = ip_hdr(skb);
 			unsigned int offset;
-			iph->check = 0;
-			iph->check = ip_fast_csum((u8 *) iph, iph->ihl);
 			offset = skb_transport_offset(skb);
 			if (iph->protocol == IPPROTO_TCP) {
 				skb->csum = 0;