bnxt_en: Add TPA structure definitions for BCM57500 chips.

The new chips have a slightly modified TPA interface for LRO/GRO_HW.
Modify the TPA structures so that the same structures can also be
used on the new chips.

Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>