net-bnx2x: dont reload on GRO change

bnx2x_set_features() forces a driver reload if GRO setting is changed.

A reload makes the ethernet port unresponsive for about 5 seconds.

This is not needed in the common case LRO is enabled, as LRO
(TPA_ENABLE_FLAG) has precedence over GRO (GRO_ENABLE_FLAG)

Tested:
 Verified that "ethtool -K eth0 gro {on|off}" doesn't blackout
 the NIC anymore

Google-Bug-Id: 8440442
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Dmitry Kravkov <dmitry@broadcom.com>
Acked-by: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>