bnx2x: Dont update vlan_features in bnx2x_set_tso()

Patrick said : "vlan_features doesn't need to be updated, the resulting
dev->features of the VLAN device is computed as the intersection of
dev->features and dev->vlan_features."

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>