bnxt_en: Expand bnxt_tpa_info struct to support 57500 chips.

Add an aggregation array to bnxt_tpa_info struct to keep track of the
aggregation completions.  The aggregation completions are not
completed at the TPA_END completion on 57500 chips so we need to
keep track of them.  The array is only allocated on the new chips
when required.  An agg_count field is also added to keep track of the
number of these completions.

The maximum concurrent TPA is now discovered from firmware instead of
the hardcoded 64.  Add a new bp->max_tpa to keep track of maximum
configured TPA.

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