bnxt_en: Retrieve hardware counter masks from firmware if available.

Newer firmware has a new call HWRM_FUNC_QSTATS_EXT to retrieve the
masks of all ring counters.  Make this call when supported to
initialize the hardware masks of all ring counters.  If the call
is not available, assume 48-bit ring counter masks on P5 chips.

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>