bnx2x: LSO code was broken on BE platforms

Make the LSO code work on BE platforms: parsing_data field of
a parsing BD (PBD) for 57712 was improperly composed which made FW read wrong
values for TCP header's length and offset and, as a result, the corresponding
PCI device was performing bad DMA reads triggering EEH.

Signed-off-by: Vladislav Zolotarov <vladz@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>