bnx2x: remove gro workaround

Removes GRO workaround, as issue is fixed in FW 7.2.51.

Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: Barak Witkowski <barak@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>