hyperv: Fix the carrier status setting

hyperv: Fix the carrier status setting

[ Upstream commit 891de74d693bb4fefe2efcc6432a4a9a9bee561e ]

Without this patch, the "cat /sys/class/net/ethN/operstate" shows
"unknown", and "ethtool ethN" shows "Link detected: yes", when VM
boots up with or without vNIC connected.

This patch fixed the problem.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>