bnx2x: Be more forgiving toward SW GRO

This introduces 2 new relaxations in the bnx2x driver regarding GRO:
  1. Don't prevent SW GRO if HW GRO is disabled.
  2. If all aggregations are disabled, when GRO configuration changes
     there's no need to perform an inner-reload [since it will have no
     actual effect].

Signed-off-by: Dmitry Kravkov <Dmitry.Kravkov@qlogic.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: Ariel Elior <Ariel.Elior@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>