Description of problem:
Boot guest with e1000e. After executing "(qemu) set_link net0 off", the value of "/sys/class/net/$nic/operstate" in guest is 'up'. but the expected value is 'down'.

Version-Release number of selected component (if applicable):
4.18.0-82.el8.x86_64
qemu-kvm-2.12.0-69.module+el8.1.0+3143+457f984c.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Boot guest with e1000e

-netdev tap,id=hostnet0 \
-device e1000e,netdev=hostnet0,id=net0,mac=fa:5e:07:b4:08:01,bus=root.2 \

2. In qemu terminal, set this NIC link off
(qemu) set_link net0 off

3. In guest, check status, it's wrongly showed "up".

1. ifconfig
   ens2: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
   inet 10.73.74.39 netmask 255.255.252.0 broadcast 10.73.75.255
   inet6 fe80::f85e:7ff:feb4:801 prefixlen 64 scopeid 0x20<link>
   ether fa:5e:07:b4:08:01 txqueuelen 1000 (Ethernet)
   RX packets 81602 bytes 6158528 (5.8 MiB)
   RX errors 0 dropped 0 overruns 0 frame 0
   TX packets 268 bytes 758903 (741.1 KiB)
   TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
   device interrupt 23 memory 0xfe640000-fe660000

1. cat /sys/class/net/ens2/operstate
   up

Actual results:
The value of /sys/class/net/$nic/operstate is wrongly showed "up" after set link down.

Expected results:
The value of /sys/class/net/$nic/operstate should be showed "down" after set link down.

Additional info:
1. virtio-net-pci works well. So it's only e1000e issue.

Reference:
1. Full cmd line:

/usr/libexec/qemu-kvm -name rhel8.0 \
-M q35,kernel-irqchip=split \
-cpu host -m 8G \
-smp 4,sockets=1,cores=4,threads=1 \
-device pcie-root-port,id=root.1,slot=1 \
-device pcie-root-port,id=root.2,slot=2 \
-drive file=/home/rhel8.0.qcow2,format=qcow2,if=none,id=drive-virtio-blk0,werror=stop,rerror=stop \
-device virtio-blk-pci,drive=drive-virtio-blk0,id=virtio-blk0,bus=root.1 \
-vnc :2 \
-monitor stdio \
-netdev tap,id=hostnet0 \
-device e1000e,netdev=hostnet0,id=net0,mac=fa:5e:07:b4:08:01,bus=root.2 \