[LRO] Fix lro_mgr->features checks

lro_mgr->features contains a bitmask of LRO_F_* values which are
defined as power of two, not as bit indexes.
They must be checked with x&LRO_F_FOO, not with test_bit(LRO_F_FOO,&x).

Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>
Acked-by: Andrew Gallatin <gallatin@myri.com>
Signed-off-by: David S. Miller <davem@davemloft.net>