This patch adds a support of VIRTIO_NET_F_SPEED_DUPLEX feature
for virtio driver.
There are two ways to specify speed of the link:
'speed' devarg
negotiate speed from qemu via VIRTIO_NET_F_SPEED_DUPLEX
The highest priority is devarg. If devarg is not specified,
drivers tries to negotiate it from qemu.
Signed-off-by: Ivan Dyukov <i.dyukov@samsung.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>