virtio-net: add cond_resched() to the command waiting loop

virtio-net: add cond_resched() to the command waiting loop

Adding cond_resched() to the command waiting loop for a better
co-operation with the scheduler. This allows to give CPU a breath to
run other task(workqueue) instead of busy looping when preemption is
not allowed on a device whose CVQ might be slow.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20230720083839.481487-3-jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Shannon Nelson <shannon.nelson@amd.com>