net/vmxnet3: keep link state consistent

net/vmxnet3: keep link state consistent

The vmxnet3 never attempts link speed negotiation.  As a virtual device
the link speed is vague at best.  However, it is important for certain
applications, like bonding, to see a consistent link_status.  802.3ad
requires that only links of the same cost (link speed) be enslaved.
Keeping the link status consistent in vmxnet3 avoids races with bonding
enslavement.

Fixes: 1e3a958f40b3 ("ethdev: fix link autonegotiation value")
Cc: stable@dpdk.org
Signed-off-by: Chas Williams <chas3@att.com>
Acked-by: Yong Wang <yongwang@vmware.com>