virtio-net: convert rx mode setting to use workqueue

This patch convert rx mode setting to be done in a workqueue, this is
a must for allow to sleep when waiting for the cvq command to
response since current code is executed under addr spin lock.

Note that we need to disable and flush the workqueue during freeze,
this means the rx mode setting is lost after resuming. This is not the
bug of this patch as we never try to restore rx mode setting during
resume.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20230720083839.481487-2-jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Shannon Nelson <shannon.nelson@amd.com>