bnx2x: Do not allow enabling LRO if disable_tpa=1

Bug fix: Do not allow enabling LRO if disable_tpa=1.

Signed-off-by: Vladislav Zolotarov <vladz@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>