This patch fixes netdev->features for Extended Socket network device.

Currently Extended Socket network device's netdev->feature claims
NETIF_F_HW_CSUM, however this is completely wrong. There's no feature
of checksum offloading.
That causes invalid TCP/UDP checksum and packet rejection when IP
forwarding from Extended Socket network device to other network device.

NETIF_F_HW_CSUM should be omitted.
Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>