bnxt_en: Allocate the larger per-ring statistics block for 57500 chips.

The new TPA implemantation has additional TPA counters that extend the
per-ring statistics block.  Allocate the proper size accordingly.

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