We can now fully support sharing the same MSIX for all mqprio TX rings
belonging to the same ethtool channel with the new infrastructure:

1. Allocate the proper entries for cp_ring_arr in struct bnxt_cp_ring_info
to support the additional TX rings.

2. Populate the tx_ring array in struct bnxt_napi for all TX rings
sharing the same NAPI.

3. bnxt_num_tx_to_cp() returns the proper NQ/completion rings to support
the TX rings in the input.

4. Adjust bnxt_get_num_ring_stats() for the reduced number of ring
counters with the new scheme.
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>