Add missing sg_init_table for sg_set_buf in virtio_net which
induced in defer skb patch.
Reported-by: NThomas Müller <thomas@mathtm.de>
Tested-by: NThomas Müller <thomas@mathtm.de>
Signed-off-by: NShirley Ma <xma@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>