bnxt_en: Retrieve hardware masks for port counters.

If supported by newer firmware, make the firmware call to query all
the port counter masks.  If not supported, assume 40-bit port
counter masks.

Reviewed-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>