virtio-net: correctly transmit XDP buff after linearizing

[ Upstream commit 5d458a13dd59d04b4d6658a6d5b94d42732b15ae ]

We should not go for the error path after successfully transmitting a
XDP buffer after linearizing. Since the error path may try to pop and
drop next packet and increase the drop counters. Fixing this by simply
drop the refcnt of original page and go for xmit path.

Fixes: 72979a6c ("virtio_net: xdp, add slowpath case for non contiguous buffers")
Cc: John Fastabend <john.fastabend@gmail.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>