be2net: Fix Endian

ETH_P_IP is host Endian, skb->protocol is big Endian, when
compare them, we should change ETH_P_IP from host endian
to big endian, htons, not ntohs.

CC: Somnath Kotur <somnath.kotur@emulex.com>
Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
Acked-by: Somnath Kotur <somnath.kotur@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>