bnx2x: code doesn't use stats for allocating Rx BDs

Previously, allocation used queue statistics directly in its calcualtion.
This change causes these calculations to be summed into the statistics,
without being affected by them.

Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>