[TCP]: Introduce tcp_hdrlen() and tcp_optlen()

The ip_hdrlen() buddy, created to reduce the number of skb->h.th-> uses and to
avoid the longer, open coded equivalent.

Ditched a no-op in bnx2 in the process.

I wonder if we should have a BUG_ON(skb->h.th->doff < 5) in tcp_optlen()...

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ehea/ehea_main.c b/drivers/net/ehea/ehea_main.c
index 0dc701e..63732d2 100644
--- a/drivers/net/ehea/ehea_main.c
+++ b/drivers/net/ehea/ehea_main.c
@@ -1300,7 +1300,7 @@
 	/* copy only eth/ip/tcp headers to immediate data and
 	 * the rest of skb->data to sg1entry
 	 */
-	headersize = ETH_HLEN + ip_hdrlen(skb) + (skb->h.th->doff * 4);
+	headersize = ETH_HLEN + ip_hdrlen(skb) + tcp_hdrlen(skb);
 
 	skb_data_size = skb->len - skb->data_len;