bnxt_en: Switch over to use the 64-bit software accumulated counters.

Now we can report all the full 64-bit CPU endian software accumulated
counters instead of the hw counters, some of which may be less than
64-bit wide.  Define the necessary macros to access the software
counters.

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>