bnx2x: Add TPA, Broadcoms HW LRO

The TPA stands for Transparent Packet Aggregation. When enabled, the FW
aggregate in-order TCP packets according to the 4-tuple match and sends
1 big packet to the driver. This packet is stored on an SGL in which
each SGE is 1 page. The FW also implements a timeout algorithm and it
honors all TCP flag, including the push flag as a trigger to halt
aggregation.

After receiving Ben Hutchings comments, we also added ethtool support,
so now, thanks to Ben's patch, when forwarding is enabled, our
aggregation is turned off using the LRO flags.

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>